Inverter, Storage and PV System Technology Industry Guide 2013

Inverter, Storage and PV System Technology

Industry Guide 2013


Industry Guide 2013

recommended by

“Inverter, Storage and PV System Technology” takes a close look at the electrical components of the PV system and its interactions, presents the latest technical developments, and gives an overview of market conditions.

Corporate portraits of international companies round off this comprehensive industry guide on PV system technology.

www.pv-system-tech.com

climate-neutral

Cover images

Front

Main image Vented stationary lead-acid battery with a liquid electrolyte. The tubular plates technology is designed to result in a large number of cycles during the batteries’ lifetime. (Photo: Tom Baerwald/HOPPECKE Batterien GmbH & Co. KG)

Small images, f.l.t.r. Taking measurements using a thermal imaging camera (Photo: Tom Baerwald/Lebherz) Central inverter in a ground-mounted installation (Photo: Tom Baerwald) String inverter in an electromagnetic compatibility (EMC) test chamber (Photo: SMA Solar Technology AG)

Back

Climate chamber test to ensure that inverters withstand extreme temperature variations (Photo: SMA Solar Technology AG)

Top information for yourvisit in Munich, Germany

The World´s Largest Exhibition for the Solar IndustryMesse München, Germany

Intersolar Europe gives you an insider advantage on cutting-edge information about the dynamic markets of the solar industry

Connect with 1,500 international exhibitorsLearn everything about the latest innovationsKeep up with future trends for continued business successGet inspired!

AZISE2013_IntverterPV_210x297.qxp:Layout 1 07.03.13 10:59 Seite 1


Industry Guide 2013

3

Foreword by K. H. Remmers, CEO Solarpraxis AG . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

The Industry Photovoltaic Plants and the Importance of Electrical Components . . . . . . . . 8 The PV Generator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Inverters and PV Plant Yield . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Inverters and Grid Integration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 Storage Systems and Energy Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 Plant Monitoring and Identifying Faults . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 Stand-Alone Power Systems and Grid-Parallel Operation . . . . . . . . . . . . . . . . . . . . . . 40 Protection against Lightning and Overvoltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 Cables and Connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 Market Situation and Forecasts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

The Companies Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54 Business Areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

ABB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58 Advanced Energy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 AEG Power Solutions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61 Bonfiglioli Riduttori S.p.A. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62 Bosch Power Tec GmbH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63 Danfoss Solar Inverters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64 Diehl Controls – PLATINUM® GmbH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65 Fronius Deutschland GmbH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66 GoodWe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67 W. L. Gore & Associates GmbH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68 Ingeteam Power Technology S.A. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69 KOSTAL Industrie Elektrik GmbH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70 KOSTAL Solar Electric GmbH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71 LTi REEnergy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72 Mastervolt International BV . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73 meteocontrol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74 Multi-Contact AG . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75 Nidec ASI S.p.A. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76 OBO BETTERMANN GmbH & Co. KG . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77 Phoenix Contact GmbH & Co. KG . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78 Power-One . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79 REFUsol GmbH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80 Saft . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81 Schneider Electric . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82 skytron® energy GmbH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83 SMA Solar Technology AG . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84 Solare Datensysteme GmbH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85 SolarMax . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86 Steca Elektronik GmbH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87

Publishers Solarpraxis AG . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90 Sunbeam GmbH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91

Important Notice, Picture Credits, Sources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92 Legal Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93

Contents

Contents

4

5

ForewordDear Readers,With the global amount of newly installed photovoltaic capacity expected to increase from today’s annual level of around 30 gigawatts (GW) to more than 300 GW per year by 2025, the develop-ment of solar technology is unstoppable.

However, the success of the energy revo-lution is no guarantee. Without a doubt, 2012 has been the most difficult year for the solar industry in a long time. Despite a marked drop in solar energy prices and many new markets emerging around the world, the market’s strong dynamism has led to considerable financial difficul-ties and even insolvencies.

This is because the high level of dy-namism was, and indeed still is, also characterized by insecure conditions: Many governments are stalling the developments by making sudden, drastic cuts to subsidy programs, and even the substantial drop in solar power genera-tion costs was unable to compensate for the insecurity felt amongst companies and customers, causing severe job losses in the industry.

Despite these difficult conditions, the PV industry was still able to demonstrate its innovative power. Up until two years ago, storage systems were only of minor interest – even in this brochure. Today, however, they are on their way towards becoming an important up-and-coming market. This is because the two sources of energy which are experiencing the greatest levels of growth worldwide are both fluctuating in nature: Unlike fossil-fuel or nuclear power stations, the amounts of electricity that solar and wind power plants feed into the grid var-ies, which is why these energy sources depend on powerful storage systems. Additionally, our electricity grids have been inherited from the age of indus-trialization. They were built in order to transport electricity from centralized coal-fired power stations – and later from large nuclear plants – to conurba-tions and industrial centers. The energy revolution changes all that: The grid of

the future not only has to distribute electricity, but must also collect power from decentralized generators.

A great number of companies are cur-rently working on storage solutions which are able to interact with the grid intelligently. This innovative strength has not yet received any political support – not even in Germany, the country which can still call itself a technological leader in solar energy.

When the announced, and admit-tedly rather meager, 50 million euros of funding for storage systems will actu-ally become available remains unclear. Negotiations with the German Federal Ministry for the Environment concerning the funding conditions had almost been concluded, and the banks had already been informed of the necessary proce-dures, when the program was suddenly shelved. While the manufacturing indus-try is working on pioneering solutions, the German government is paying no more than lip service.

Storage systems and the integration of decentralized storage into the power grid will play a decisive role in the reor-ganization of our power supply in the future. The course has to be set now be-cause despite all the setbacks it is facing, renewable energy will continue to flour-ish. Intelligent storage systems will not only steadily increase in importance, but will soon become essential. The industry has understood this state of affairs. Now it is high time for governments to grasp it as well.

Kind regards,

Karl-Heinz Remmers,CEO Solarpraxis AG

Karl-Heinz Remmers, CEO of Solarpraxis AG

Foreword

6

7

The Industry

8

Photovoltaic Plants and the Importance of Electrical ComponentsGrid-connected PV plants have become so numerous even in some parts of Germany that on sunny days their output exceeds consumption in the region. This is why, especially in industrialized countries, the further ex-pansion of photovoltaics must go hand in hand with the expansion of centralized and decentralized storage systems so that an increasing part of this surplus can be consumed close to the source. Furthermore, with the growing importance of on-site consumption and more and more grid-connected PV systems being equipped with battery storage, the differences between on-grid and off-grid photovoltaics are slowly disappearing, and inverters are turning into energy management systems.

Battery power plant in the technology center of a renewable energy systems developer

PHO

TO: YO

UN

ICO

S TECH

NO

LOG

IEzENTRU

M

Photovoltaic Plants and the Importance of Electrical Components

9


Power generation and grid services

A photovoltaic plant (PV plant) that feeds all the power it generates into the grid essentially consists of the following com-ponents:

• PV generator (solar modules)• support structure (mounting frame) • generator junction box (GJB)• inverter • monitoring system • feed-in meter • grid connection • direct current (DC) and alternating

current (AC) cabling

Careful planning is critical to achiev-ing the optimum balance between a plant’s components. These are continu-ally undergoing further development to

increase yield and efficiency. When inte-grating these components into a single system, the different module types avail-able (modules with crystalline silicon so-lar cells or modules based on the various thin film technologies) must be given just as much consideration as the ever-increasing functions of the inverter.

Photovoltaic systems need to do more than simply feed energy into the grid if they are to make an adequate contribu-tion to the power supply. Installations must also play a role in stabilizing the grids, for example by supplying reac-tive power, supporting grid frequency or keeping an installation on the grid when there are grid failures. This is why, as the systems’ intelligence centers, inverters are also increasingly required to perform grid services.

From purely feeding the maximum amount of energy into the grid through providing grid services, the inverter must now also develop itself into an energy manager that assesses the different op-tions available for utilizing the solar pow-er and then identifies the most profitable solution in each situation.

Private power supply is becoming in-creasingly distributed. Ever more PV sys-tem operators are themselves consum-ing the power generated on their roofs. PV systems technology is set to develop further as a result of this. This will par-ticularly affect inverters, as they guide the solar power either into the house-hold network, a power storage system or the public grid, depending on supply and demand.

Ideas are transformed into marketable products in the industry's development departments.

PHO

TO: SM

A SO

LAR TEC

HN

OLO

GY A

G

PHO

TO: TO

M BA

ERWA

LD

The PV plant in Senftenberg (Brandenburg, Germany) was the

largest solar park in the world when it was commissioned in 2011.

It comprises three units with a total output of more than 160 MW.

10

Centralized and decentralized storage systems

Accumulators (batteries) offer a great option for storing surplus solar power and then feeding it into the domestic grid as required. This provides a new ap-plication for traditional lead-acid batter-ies, although new (e.g. lithium-based) storage systems are also being devel-oped. New developments are still very expensive, meaning that initially their market is expected to grow slowly. If the necessary expansion of storage ca-pacity is to keep up with the increasing amount of power being generated, the specific costs per stored kilowatt hour and per kilowatt hour withdrawn from storage (euros/kWh) must be reduced while the cycle life of batteries must be increased.

The market for storage systems is still too young, however, to foresee which technologies will secure a large foothold. A likely future scenario will involve a mix-ture of distributed, short-term storage systems and large, seasonal storage sys-tems that are capable of storing surplus energy for several weeks or even months.

Off the grid

Photovoltaics is not just growing in im-portance in regions supplied by the pub-lic grid. In areas without grid connection – or where diesel generators are still the main power source – and where sufficient insolation is available, PV plants are able to generate electricity relatively cheaply. This is because off-grid supply is usually cheaper than connecting to a far-away grid. As a result, ever growing numbers of

standalone PV systems are springing up in sparsely populated or technologically less developed regions in Asia and Africa. Hybridizing diesel power supply systems by combining them with a PV plant in or-der to reduce fuel costs is already cost-ef-fective today. PV systems are also increas-ingly popular in areas with an unreliable public grid due to frequent grid failures and power fluctuations. Here they oper-ate in parallel to the grid and support it when necessary. Off-grid and on-grid sys-tems are growing together.

1.

1.

0 0 1 2 3 4 6 7

2.

2.

3.

3.

5. 7.

6.

8.

4.

9.

10.

11.

12.DC AC

1. PV generator (solar modules)2. Solar module junction box3. Solar cable connector4. Power optimizer5. Generator junction box (GJB)6. Monitoring solutions7. Inverter8. Fuse box 9. Consumer10. Battery storage11. Import/export meter12. Grid supply

PV system components (possible designs)


11

The PV Generator Electrically connected solar modules make up a PV generator, which generates electrical power dependent on insolation and temperature. The output of a solar generator is therefore not only determined by the efficiency of its modules, but also by how well those modules exploit the strength and spectrum of the insolation, and how they react to the module temperature.

PHO

TO: A

CTIV

SOLA

R GM

BH

Perovo Solar Park in Crimea (Ukraine) with an output of 100 MW. The plant uses a turnkey monitoring system that is integrated into the inverter stations.

The PV Generator

12

Efficiency and surface area

The photovoltaic effect in solar cells can be used to generate power in several ways. Solar cells are made from a variety of different materials, with crystalline silicon being the most common. Thin-film cells made from cadmium telluride (CdTe), copper indium/gallium disulfide/diselenide (CIGS), amorphous silicon (a-Si) and amorphous/microcrystalline sili-con (a-Si/μc-Si) are also extensively used. Several solar cells are connected together to make up a module, several modules in series are connected together to form strings and several strings in parallel create the solar generator. The electri-cal properties of crystalline modules are markedly different from those of thin-film modules and must be taken into account in order to achieve the highest possible yield in a given location.

Since modules made from crystalline silicon are generally more efficient than thin-film modules, they are used wherev-er space is at a premium, such as on the roofs of single-family homes. Module ef-ficiency therefore solely affects the space requirements for the PV plant: In the case of crystalline solar modules, an area of around five to nine square meters (m2) is needed to achieve an output of one kilo-watt peak (kWp), whereas for thin-film modules the area required for the same output is between 8 and 20 m2 – depend-ing on the technology used.

On the one hand, this means that the cost of support structures and installa-tion is higher for thin-film solar modules as surface area efficiency is usually lower, and that the modules themselves must therefore be somewhat cheaper in a turnkey system of the same price. On the

other hand, the area required only has an indirect effect on the specific yield of a PV plant, which is indicated in kWh/kWp. To calculate the specific yield, the electricity output (in kWh) is related to the installed system capacity (in kWp) so that module efficiency becomes immaterial. All in all, with trouble-free operation, the specific yield and costs of photovoltaic installa-tions – and thus their profitability – are roughly the same whether crystalline silicon modules or thin-film modules are used.

The cost of land plays a secondary role when installing ground-mounted sys-tems, as economies of scale come into play in such installations. In recent years, ground-mounted systems have there-fore often been built using thin-film so-lar modules, though the astonishingly sharp drop in prices for crystalline silicon modules has now caused the thin-film market share to diminish again. This is not only the case with ground-mounted installations but in all market segments.

Crystalline silicon solar cells are particu-larly responsive to long-wave solar radia-tion. In contrast, thin-film modules make better use of the short and medium-wave range of the solar spectrum. In cloudy con-

Cells made from different materials have different efficiencies. PV array surface area depends on the type of cell used.

Cell material Module efficiency

Surface area need for 1 kWp

Monocrystalline silicon 13–19% 5–8 m2

Polycrystalline silicon 11–15% 7–9 m2

Micromorphous tandem cell (a-Si/μc-Si) 8–10% 10–12 m2

Thin film copper-indium/gallium-sulfur/diselenide (CI/GS/Se)

10–12% 8–10 m2

Thin-filmcadmium telluride (CdTe) 9–11% 9–11 m2

Amorphous silicon (a-Si) 5–8% 13–20 m2

PHO

TO: TO

M BA

ERWA

LD

Quality testing by independent experts guarantees that the completed PV plant

is consistent with its planning docu-ments and yield reports.

The PV Generator

13

15

10

5

0

-5

-10

-15

-20

MPP output dependent on temperatureRe

lati

ve c

han

ge (%

)

Temperature (°C)

STC (Standard Test Conditions)

-5 5 15 25 35 45 55 65

PMPP

cSi

PMPP

aSi

PMPP

CdTe

PMPP

Power maximum power point

ditions, the spectrum that hits the ground has a higher proportion of shortwave light, which is best exploited by amor-phous thin-film modules. CdTe, CI/GS/Se and microcrystalline thin-film modules, on the other hand, are best suited to ab-sorbing medium wavelengths. In general, thin-film modules are ideal for sites which experience a high proportion of diffuse in-solation due to frequent cloudy weather, or temporary or partial shading. Further-more, they offer advantages when the ori-entation of the solar modules (for example on an east- or west-facing roof) is not ideal.

Despite their lower efficiency, which is measured in laboratory simulations un-der artificial sunlight with an intensity of 1,000 watts per square meter (W/m2), at module temperatures of 25°C and with spectral irradiance at an air mass of 1.5 (standard test conditions, STC), the elec-tricity yield of thin-film modules can be comparatively high under certain condi-tions. On the one hand, this is linked to the temperature coefficient gradient, which is markedly different to that of a crystalline module. On the other, the specific yield in kWh/kWp is a variable which is not relat-ed to surface area, meaning that the lower efficiency of individual modules becomes irrelevant for comparison.

The temperature coefficient

The temperature coefficient of voltage – and consequently also the module out-put determined by voltage times current – is negative. This means that the module output and voltage (when compared to the data sheet and nameplate capacity) decrease at high temperatures (higher than the reference temperature T=25°C under STC). Conversely, they increase at low temperatures. The temperature coef-ficient of current is both very small and positive, so currents will only alter to a very small degree as a result of tempera-ture fluctuations, therefore only exerting very little influence on module output.

Here is an example with some typical val-ues: Under STC, a given solar module with crystalline silicon solar cells has a nomi-nal output of 200 watts peak (Wp) and the temperature coefficient of output is –0.5%/kelvin (K). This means that the output of this module would decrease by 5% for every temperature increase of 10 K. If this module were to reach a tempera-ture of T=55 °C, the output would drop by 15%, i.e. the 200 Wp module would “only” supply 170 Wp. Inversely, at a module temperature of T=5 °C, its output would increase to 220 Wp. Thin-film modules

are characterized by a lower temperature coefficient of output, typically –0.3%/K. This means that at a module tempera-ture of T=55 °C, the solar module would only show a drop in output of 9%.

Insolation can heat PV modules to as much as 70 °C. For this reason, they are installed so as to ensure that air can circulate to provide sufficient rear ven-tilation. Where rear ventilation is not possible, for instance if the modules are integrated into the roof or façade of a thermally insulated building, thin-film modules are better suited as their actual output is less dramatically impaired by high temperatures.

(f. l. t. r.:)Roof-mounted installation in Germany

Carport in Tongeren (Belgium) with the PV system inverters on lefthand side

Ground-mounted installation in France

Temperature coefficient of the output power in MPP (PMPP): As the temperature increases, the PV module output drops steadily. Crystalline modules (cSi) are far more severely affected by this than thin-film modules (aSi and CdTe).

PHO

TO: C

OLExO

N EN

ERGY A

G

PHO

TO: REFU

SOL G

MB

H

PHO

TO: SIEM

ENS A

G

The PV Generator

14

Bypass diodes against overheating

Since a single solar cell is only able to generate around 0.5 volts (V), a number of cells within a module are connected in series to form a string. This has the disad-vantage of making the module extreme-ly sensitive to partial shading because when a shadow is cast on a cell, e.g. from a chimney, dormer or an antenna, the cell can no longer generate power, turning it from power generator to power con-sumer. As the weakest link in the chain, the cell restricts the power output of the entire string.

Shaded cells do not generate electricity, while the other, fully illuminated cells in the string remain completely active and drive their power through the shaded cell, which converts that power into heat. In extreme cases, this leads to a “hot spot” being created in the cell, which can melt a hole in the cell material. A bypass diode, which bypasses the module string containing the shaded cell, is therefore used to steer the electricity past the pas-sive cell.

A bypass diode usually bypasses 20 to 24 cells. Today, modules consisting of 60 to 72 cells are often equipped with three bypass diodes which are located in the module junction boxes. As each diode by-passes a part of the module, in the case of very slight shading, only some of the output of all the series-connected cells making up the module will be lost.

It would therefore be ideal if each solar cell could be equipped with a bypass di-ode. Unfortunately, the junction box does not provide enough space for this. To get

around the problem, several manufactur-ers have started to laminate “string bypass diodes” into their modules. This allows a greater number of diodes to be used than will fit in the junction box, and shading tol-erance is noticeably increased as a result.

Overall, shading has the same effect as sharply reduced insolation: a decreased flow of current. This applies in principle to both crystalline and thin-film mod-ules. However, the latter benefit from the strip-like arrangement of their solar cells, as it is relatively uncommon for long, nar-row, thin-film solar cells to become com-pletely shaded. The reduction in output of a thin-film module is therefore usually proportionate to the shaded area.

Where losses are expected due to high operating temperatures or shading, thin-film modules are often given preference over crystalline silicon models.

Concentrated photovoltaics

As efficiency increases with greater radia-tion intensity, the efficiency of solar cells can also be raised by concentrating the sunlight that falls on them with mirrors or lenses. In theory, multiplying the con-centration of sunlight by 100 produces a 20% increase in output.

Concentrator cells fitted with Fresnel lens-es can be combined relatively easily into modules. Modules that are ready for mass production achieve an efficiency of around 25% with a concentration factor of 500.

As diffused sunlight reaches the lens system from all directions, it cannot be focused on the cells. Consequently, con-

centrator modules only utilize the part of the global insolation that reaches them directly and must follow the sun on a dual-axis tracking system. Their output is therefore at its highest along the earth’s sun belt.

Module junction box

Module junction boxes connect solar cells to the outside world by joining the connection cables of the cell strings and interconnecting them with the bypass di-odes and the module connection cables. To prevent moisture from entering the module junction box, it is waterproofed and often sealed with silicon.

Little by little, electrical functions are be-ing incorporated into the module junc-tion box to provide additional safety or increase the yield. DC/DC converters ensure that the voltage output is opti-mal for the inverter, irrespective of shad-ing and temperature. Even performance boosters (e.g. power optimizers – see “In-verters and PV Plant Yield”) can be incor-porated into the junction box. Each mod-ule will then have its own MPP controller. PV generator safety can be increased by automatic fire prevention systems, also located in the module junction box.

Reflection losses

In order for yield to be increased even fur-ther, reflection losses must also be taken into account. Modules with anti-reflec-tion glass are already in use, but are rela-tively expensive. Reflection losses can, however, be virtually eliminated if the PV generators are equipped to track the sun’s movement on a dual axis, though

Bypass diode

cell 1

cell 20

cell 21

cell 22

cell 2

Bypass diode

The reduced output and possibility of damage to cells and modules caused by shading can be

mitigated by the use of bypass diodes. The diode short circuits the affected area and allows the

current to bypass it.

The PV Generator

15

this involves relatively high additional expense for the mechanical system. Such outlay is really only worthwhile if ad-equate additional yield can be achieved, i.e. if the PV system is installed at a site with a high proportion of direct insola-tion, preferably along the earth’s sunbelt. This applies similarly to concentrating sunlight with mirrors or optical lenses.

Yield can also be increased by active cool-ing. Here, cooling modules on their rear side produces warm water or warm air in addition to electricity. All in all, the advantages of this method are, however, too few for it to have become well-estab-lished.

Aging processes

Since they contain no moving parts, so-lar modules normally age very slowly. As long as their materials (glass, solar cells, plastics, aluminum) have been carefully selected, they are also suffi-ciently weather resistant. If a system is installed in such a way that corro-sion cannot take hold, it can achieve a service life of 20 years or more. The as-sembly frame should be designed to en-sure that there are no corners or niches where dirt, leaves and other deposits could collect, and standing water should also be avoided. Different metals may only be used together if it can be guar-anteed that no electrochemical reaction will take place. This particularly applies to the screws and clamps in the support frame that holds the PV generator.

In the early days of PV technology, the transparent conductive oxide (TCO) coat-ing, applied to the illuminated upper face

of most thin-film modules to conduct current, was often damaged by corro-sion. TCO corrosion is irreversible and leads to severe output losses. Such dam-age predominantly occurs in the event of high voltages caused by earth leak-age currents. Grounding the generator’s negative pole can prevent TCO corrosion, though it also precludes the use of sev-eral inverter types.

Generator junction box

The modules are connected in series to form a string. The cumulative voltage of the individual modules gives the string voltage, which must be calibrated to the system voltage of the inverters. Strings of equal length are then connected in parallel to make up the PV generator, where the output power of the strings is cumulative. Multiple string cables from the PV generator are consolidated using Y-adapters or joined in a GJB.

The GJB is located close to the modules and connects several strings in parallel, meaning that only one positive and one negative cable – albeit with large cable cross sections – must be laid from each junction box to the downstream inverter. It can also perform additional safety-related functions, such as those of string fuses or overvoltage conductors. If thin-film modules are used which are not re-verse current proof, blocking diodes must also be employed. In addition, there are certain components which may be posi-tioned in several different locations with-in the system. For example, the main DC switch could be a part of the GJB or could be integrated into the inverter.

1. Blocking diodes2. DC switch3. Surge suppressor4. String fuses

1. 2. 3. 4.

Generator junction box

PHO

TO: D

EUTSC

HER zU

KU

NFTSPREIS

Multi-junction solar cells are used in concentrated photovoltaics. They capture different wavelength ranges of sunlight and are combined with lenses that concentrate sunlight.

The PV Generator

16

Inverters and PV Plant YieldMajor discrepancies exist between power generation with PV modules and the requirements of the public grid. The job of the inverter is to connect the systems with each other and to feed the solar power into the grid with the highest possible efficiency. A PV installation’s yield is, therefore, just as heavily dependent on the reliability and efficiency of the inverter as on the orientation, interconnection and quality of the PV modules.

Construction of an inverter station in a large solar park

PHO

TO: TO

M BA

ERWA

LD/PA

RAB

EL AG

Inverters and PV Plant Yield

17

Automatic search for the maximum power point

The inverter represents the link between the solar generator and the public pow-er grid, and must therefore perform sev-eral tasks simultaneously. The most im-portant of these are MPP tracking and converting the solar modules’ DC into grid-compatible AC. Recently, it has also assumed new tasks in supporting the public grid (see also “Inverters and Grid Integration”).

An inverter is a power converter which converts the DC supplied by the PV gen-erator into AC that has the same voltage and frequency as the grid. If required, this conversion can occur with a speci-fied phase shift, in order to feed reactive power into the grid (e.g. in the event of grid failure) and lend it support. Thanks to state-of-the-art power electronics, converting DC into AC now only incurs minimal losses. The term “grid-tie invert-er” (GTI) is also used for the device, as it is specifically geared toward the require-ments of the public grid.

In order to ensure that it always feeds in the maximum power output, which is dependent on the current insolation and temperature, the inverter automatically searches for the PV generator’s optimal operating point, or “maximum power point” (MPP). The MPP must be continu-ously tracked to achieve optimum yields. The current and voltage of the PV genera-tor fluctuate widely owing to changes in insolation and temperature, and thus lead to a varying current-voltage (I-V) curve with different MPPs. Modern inverters are designed to always locate the MPP with precision and to follow its movement im-mediately. Such rapid tracking of the MPP enables the maximum possible output of the PV generator to be utilized.

In addition to tracking the MPP and con-verting DC into AC, the inverter performs other critical tasks: It plays a part in sys-tem monitoring, and collects and stores information, such as operating data, that is necessary to analyze the efficiency of the PV plant. It also displays error mes-sages and sends them to a computer when required. Furthermore, it monitors the grid connection and checks if this has failed or been switched off. Of late, invert-ers have also become responsible for con-trolling fault ride-through and supplying reactive power to stabilize the grid.

Cell

curr

ent (

A)

Cell power output (W

)

0

I-V curve of a crystalline silicon solar cell

0

1

2

1.2

0.8

0.4

3

4

Cell voltage (V)0 0.2 0.4 0.55

Short circuit current

Open circuit voltage

MPP

The open circuit voltage (VOC) is around 0.5 V. At the maximum power point (MPP) of the

curve, the voltage is about 80% of the open circuit voltage (VOC) and the current is about

95% of the short circuit current (ISC).

Insight into the manufacture of string inverters

PHO

TO: SM

A SO

LAR TEC

HN

OLO

GY A

G


18

European and Californian Efficiency

As a result of converting the DC, losses are incurred which can be relatively high within the partial load range of the in-verter (0 to 20% of the rated power), but which are usually less than 5% at the rated output. Inverters usually achieve maximum efficiency at around half the rated output; some of them even reach over 98%.

The gradient of the efficiency curve is an important factor in inverter design, as they should be operated in the partial load range for as few hours as possible each year. The time curve of a PV genera-tor’s output in a given location is crucial here. Because the PV generator will only rarely supply its full rated output, it is es-pecially important to know the probabil-ity of different outputs occurring.

The European efficiency standard (valid for the type of irradiance level found in Central Europe) is a method which ena-bles different inverters with different ef-ficacy curves to be compared by taking into consideration the amount of time the inverter can be expected to operate at particular percentage loads/levels of solar insolation:

ηEUR = 0.03 η5% + 0.06 η10% + 0.13 η20% + 0.1 η30% + 0.48 η50% + 0.2 η100%

For regions with high solar radiation – approximately 1,200 kWh/cubic meter (m3) annual global irradiance upon a horizontal surface as in southern Europe – Californian Efficiency leads to more ap-propriate results. According to different conditions of radiation the formula is:

ηCEC = 0.04 η10% + 0.05 η20% + 0.12 η30% + 0.21 η50% + 0.53 η75% + 0.05 η100%

Dimensioning

Where moderate solar radiation is preva-lent, but full insolation only rare, an in-verter which has a much lower rated out-put that that of the PV generator should be selected.

Undersizing the inverter in this way has the advantage that it will operate more frequently in a higher output range, and will thus be more efficient. The disad-vantage of this system design is that the inverter will become overloaded more rapidly if the level of insolation is high. Owing to the inherent output limita-tions, energy will effectively be wasted, as it is not possible to use all the energy generated by the solar installation.

The operator must therefore decide whether solar energy yield or economic gain should take precedence. Maximum profitability can also be achieved with slightly undersized inverters, though at times this may be overloaded and energy yield will be diminished as a result. This setup is, however, also less expensive, a saving which can compensate for yield losses in many cases.

European Efficiency

P5

P10

P20

P30 P

50P

100

0%

50%

100%

3%6%

13%10%

48%

20%

3%6%

13%10%

48%

20%

η=91.8%

η=85.9%

η=95.8%

η=96.4% η=96.0%η=94.8%

η=91.8%

η=85.9%

η=95.8%

η=96.4% η=96.0%η=94.8%

The inverter in this example has a European Efficiency of 95.5%. The maximum efficiency is 96.4%, but it only operates at this level of ef-ficiency when the inverter is operating at 50% of its nominal rating.

PHO

TO: TO

M BA

ERWA

LD

PV-Generator with polycrystalline modules


19

Owing to the effects of temperature de-scribed above, it was initially widespread practice to design AC inverter output to be up to 25% lower than the rated gener-ator output under STC. However, in view of the additional tasks now performed by inverters (e. g. supplying reactive power), it is now recommended that such drastic subdimensioning be avoided. Moreover, the accuracy of weather data has also improved, and it has come to light that short radiation peaks occur more fre-quently than expected, meaning that the rated inverter capacity should not be “too small” compared to the rated capacity of the solar modules.

Working on the basis that a maximum 0.5% of the energy generated should be lost due to output limitations, it is now recommended that an inverter’s rated output should be no more than 10% low-er that the STC rated output of the solar generator. Many renowned experts even argue that the practice of subdimen-sioning inverters should be abandoned completely. With regard to the inverter’s new task of supplying reactive power, the rated capacity of the solar generator and inverter should be roughly the same. Debates surrounding economically viable system design are ongoing.

Autonomous operation

The interconnections within a solar gen-erator represent “classic physics”: Con-necting individual modules in series al-lows the voltage to be increased, while connecting strings in parallel augments the current. The inverter input voltage is determined by the number of mod-ules connected in series to form a string, whereas the input current is determined by the number of strings. In each case, the “window” between the minimum and maximum inverter voltage must be tak-en into account, as must the maximum current carrying capacity. Inverters are connected directly to the public power grid and generally feed three-phase volt-age into the low voltage grid. For smaller installations with inverter capacities of up to 4.6 kilowatts (kW) (or 4.6 kilovolt-amperes, kVA to be precise), single-phase feed-in is also possible.

Thanks to their high efficiency and the excellent quality of power they deliver to the grid, self-commutated inverters have gained a strong foothold in the market. Such inverters contain a microprocessor to create the on and off signals for the electronic circuit breaker. This switching frequency is much higher than the grid frequency. By rapidly chopping the DC supplied by the PV modules, signals are created which best simulate sine func-tion. During pulse pauses, the current is temporarily stored in the input capacitor.

Because the inverter is not controlled by the grid, but works autonomously, it also would feed-in power when the grid is switched off, for example in the event of maintenance work. In order to avoid endangering the grid operator’s electri-cians, the system is required to have a protective circuit which automatically disconnects the inverter from the public grid if its voltage or frequency deviates from the authorized limits. Two automat-ic load break switches are used to ensure safety. A common design concept for this automatic disconnection device (ADD) is the “mains monitoring unit with allocat-ed switching devices connected in series” (MSD – see “Inverters and Grid integra-tion” ). Grid and plant protection has now become compulsory in Germany.

PHO

TO: SPU

TNIK

ENG

INEERIN

G A

G

String inverters safeguard plant yield by minimizing both losses through DC voltage and AC voltage cables.


20

Inverters equipped with transformers

The use of transformers in inverters sim-plifies the conversion of AC to match the grid voltage level, but involves magnetic and ohmic losses, and increases the de-vice’s weight. Furthermore, far from oper-ating silently, it draws attention to itself with a low-pitched humming noise. For this reason, high frequency transformers are often used instead of 50 hertz (Hz) models. They are smaller, lighter in weight and more efficient, but require more complex power electronics.

If the DC supplied by the PV generator is greatly above the crest value of the grid voltage, the transformer becomes techni-cally redundant. In addition, buck-boost converters can be employed to expand the input voltage range of an inverter and adjust it to suit different PV gen-erators. Owing to their higher efficiency, transformerless inverters are now well-established on the market.

Since removing the transformer also en-tails the loss of galvanic isolation, a DC-sensitive fault protection switch needs to be included. A further disadvantage of transformerless inverters is a slight in-crease in electromagnetic radiation (elec-trosmog). These inverters should there-fore be installed in a cool, dry place away from living rooms or bedrooms.

Inverter concepts

Recent times have seen the construction of ever larger PV plants. As the modules used here are the same as those used in smaller installations, tens of thousands of them are required to build megawatt-range solar power plants. The fact that photovoltaic generation involves so many small elements means that, depending on the power rating, several options are available for feeding into the grid.

Today, inverters come in so many differ-ent sizes that, in principle, each module could be fitted with a customized invert-er. Such module inverters essentially en-able optimum adjustment to the MPP of each individual module. The AC output of these “micro inverters” can be easily con-nected in parallel, eliminating the need for DC cabling. Though easy to install on the rear side of the module, the devices have relatively low efficiency and high specific costs. To date, these small invert-ers are only used in special applications, such as installations with an output of between 3 and 5 kW designed for con-sumption at source.

Alternatively, all module strings can be connected to one sole inverter – a central inverter. This requires that all modules be exposed to the same insolation condi-tions (in particular: same orientation and pitch, no temporary shading). Central inverters have proven successful in both small and large-scale PV installations. To-day, particularly in large-scale PV plants, a variant of the central inverter with three to four inverters in hierarchical order (master and slave) is used.

While insolation is low, only the master is active, but as soon as its upper output limit is reached, as insolation increases, the first slave is switched in. The charac-teristic curve of the master-slave unit is composed of the curves of the individual inverters, and therefore displays higher efficiency in the lower output range than a central inverter. To ensure that the workload is distributed evenly among the individual inverters, master and slave are rotated in a fixed cycle, which could be that each morning the inverter with the fewest operating hours starts as the master.

In addition to module and central invert-ers, string inverters provide a third option, enabling the MPP of each string to be tracked individually. This solution is ideal where strings receive different degrees of shading throughout the day, caus-ing individual strings to have different operation points. Here, the electricity is fed into the grid by several, independent string inverters. A further variant of the string inverter is the multistring inverter, which combines several MPP trackers in one device.

DCAC

4.

5.

1. PV generator2. Generator junction box3. DC switch4. Inverter5. Grid supply

1.

2.

3.

Central inverter

The PV array consists of several strings of series connected modules. The whole of the in-

stallation is served by a single central inverter.


21

Optimization using individual MPP controllers

Given that each module in a string has its own MPP, controlling the MPP of a string is always a compromise which can result in losses. Inverters with separate MPP controllers have recently been developed to get around this problem.

These “power optimizers” – sometimes also called power maximizers depend-ing on the company – equip each mod-ule with its own MPP controller, which is housed in the module junction box. In this way, each module is able to generate electricity at its optimal operating point, uninfluenced by the other modules to which it is connected in series. This im-proves the PV generator’s efficiency, ena-bling it to achieve a higher power yield.

The power optimizers must be suitably equipped to communicate with each in-verter, if possible without the need for an additional interface. In addition, the electronic components are required to be able to withstand weather conditions (in particular temperature changes between day/night and summer/winter).

Opinions on the actual efficiency of the different systems are divided. Advocates argue that they are particularly useful if a PV generator’s strings are exposed to dif-ferent levels of insolation in the course of a day. Then, for instance, temporary shad-ing on individual modules no longer im-pairs the yield of the system as a whole.

An enhanced version of the power op-timizer was recently launched onto the market as the Module Maximizer. This

device not only tracks the MPP, it also records the output data of a module at any given moment and sends this to the central monitoring system. This allows drops in the performance of individual modules to be detected straight away. Moreover, the Module Maximizer allows operators to disconnect the DC output of individual modules from the central monitoring center if this becomes nec-essary for maintenance work or in the event of a fire.

Specific inverter functions are performed by power optimizers and Module Maxi-mizers, and are thus moved upstream within the module configuration. It re-mains to be seen whether these develop-ments will actually become widespread, or whether they will remain a niche ap-plication.

1.

2.

3.

1. PV generator2. Inverter3. Grid supply

Module inverters

DCAC

3.

4.

1. PV generator2. DC switch3. Inverter4. Grid supply

Single string inverters

2.

DCAC

Single-string inverters take a single string of seriesconnected modules. Each string has its own inverter.


22

Inverter lifespan

Long-term experience shows that in-verters can operate fault-free for ten to twelve years on average before repairs or replacements become necessary. Regular maintenance may increase the lifespan of inverters, but they will never last as long as solar modules (30+ years).

Inverters are used in many different envi-ronments: both indoors and outdoors and in almost all climate zones. The most im-portant factor limiting where an inverter may be installed is the maximum permis-sible temperature at rated power. Where the operation of the inverter or the am-bient temperature could cause this to be exceeded (e.g. if the inverter is installed in an uninsulated roof structure), active cooling becomes necessary. However, the use of ventilators entails further risks, for example when inverters are installed in agricultural buildings. Here, if incorrectly installed, the ventilator can draw grain dust or ammonia vapors into the inverter, which can restrict ventilator operation or induce corrosion. In order to increase ser-vice life, particular attention must there-fore be paid to ensuring that an inverter’s individual components cannot overheat. In addition, they must be kept free from dust, damp and aggressive gases.

If a central inverter is used in ground-mounted installations, it will generally require its own operating room to pro-tect it from dust, moisture and high am-bient temperatures. It can, however, also be stored in housing suitable for outdoor use. To prevent any dust from entering, the air cooling system is replaced by a liquid cooling system, meaning an oper-ating room is no longer necessary.

PHO

TO: TO

M BA

ERWA

LD

Manufacture of a central inverter

PHO

TO: REFU

SOL G

MB

H

As inverters generate heat while converting DC power to AC power, protection from

overheating is crucial.


23

Inverters and Grid IntegrationIntegrating increasing amounts of solar energy into the public power supply puts various demands on PV plants. For example, special protective devices are required to prevent the risk of danger in the event of mains interference. The more PV plants feed into the public grid, the greater the demands placed on the grid services that they must perform. This is why inverters are incorporated into the grid management system.

Thin-film roof-mounted installation boasting an output of 1 MW and equipped with string inverters in Bitterfeld (Germany)

PHO

TO: REFU

SOL G

MB

H

Inverters and Grid Integration

24

High demands for feeding in power

Guidelines and standards regulate ex-actly how PV plants should be connected to the public grid, which gives rise to two highly important requirements. Firstly, when solar power is fed into the grid the power quality of the grid should not be reduced. Secondly, personal safety must be ensured in the event of mains inter-ference. Another requirement has also recently gained importance: Instead of shutting down at the first sign of a fault (fault ride through), PV plants should support the power grid and perform grid-related control functions.

The requirements for power feed-in are clearly defined: The grid requires sinusoi-dal AC with stable voltage and frequency, and the harmonic component limits are regulated in guidelines and standards. Modern inverters meet these power quality requirements, yet in some cases limits may be exceeded.

Voltage and frequency stabilities are high in the fully-developed, close-meshed grid supplied by large thermal power sta-tions, and solar power can usually also be injected without problems, even in large quantities.

The further away the feeding point from large power plants, the greater the re-quirements that are placed on grid feed-in. As a general rule, when electricity is drawn from the grid, the grid voltage falls, and when power is fed in it increas-es. Particularly when PV plants feed into rural grid structures or grid branch lines, this can cause an increase in voltage that exceeds the specified limits.

When a large amount of energy is con-sumed, the voltage in these weak grid spurs decreases, meaning that the act of feeding in decentralized solar power supply counteracts this decrease in volt-age and, in turn, supports the grid. Mea-sures need to be taken to inhibit exces-sive increases in voltage during periods in which an especially high level of power is being fed-in and very little is actually being consumed. A further consequence is that – particularly when grid feed-in is high and consumption is low in a particu-lar area of the grid – the flow of current can reverse in the power grid, and not all grids are prepared for this yet.

Disconnection devices

The grid operator stipulates that a pro-tective device be used between the pow-er generating plant and the grid, which can disconnect the plant from the grid when necessary. Its primary function is to ensure personal safety, because if the grid is shut down to carry out repair or maintenance work, power generating plants could continue to feed energy into the grid and put the safety of staff at risk.

With smaller PV plants, this task is per-formed by an ADD or a manual discon-nection device to which the grid operator has permanent access. An ADD recog-nizes grid failures and cutoffs, as well as changes to voltage and frequency which exceed the authorized limits, and discon-nects the PV plant from the grid.

PHO

TO: TO

M BA

ERWA

LD

Substations collect decentrally generated solar energy and transform it into a higher voltage level before it is transported to the centers of

consumption.

PHO

TO: TO

M BA

ERWA

LD

Laying cables during the installation of a ground-mounted system


25

Until 2004, only the use of an MSD as an ADD was permitted in Germany. The MSD measures grid impedance and is able to recognize power failure and cutoff on the basis of impedance jumps. Since 2005, other grid monitoring methods have been authorized: These include evaluat-ing the harmonic components, measur-ing the deviation of grid frequency and three-phase voltage monitoring.

An external grid and plant protection device has now replaced the use of both MSD and ADD. As of January 1, 2012, this has been officially enforced by the “VDE Application Guide VDE-AR-N 4105” (Gen-erators connected to the low-voltage distribution network – technical require-ments for the connection to and parallel operation with low-voltage distribution networks). The grid and plant protection device monitors all relevant grid param-eters, isolating the PV plant from the grid if excessively high or low voltages or ab-normal fluctuations in frequency occur at the feed-in point. The PV plant is au-tomatically reconnected to the grid once the voltage and frequency have returned to acceptable levels.

Static and dynamic support

In Germany, large-scale PV plants which feed into the medium-voltage grid must provide certain grid services in accor-dance with the country’s Medium Volt-age Directive (Mittelspannungsrichtlin-ie). In addition to a device facilitating power reduction, these include static and dynamic grid support. Control algorithms are therefore developed for inverters in order to control voltage and frequency fluctuations. Adherence to the Medium Voltage Directive has been compulsory since January 1, 2009, although transi-tional periods apply. Comparable provi-sions are contained in the Low Voltage Directive (Niederspannungsrichtlinie), meaning that even small and medium-scale PV installations are now also re-quired to perform grid services.

The performance-reducing device is pri-marily designed for PV plants with out-puts of more than 100 kW. These have to be fitted with a technical device designed to reduce feed-in capacity, such as a ripple control receiver and a device that moni-tors the current power feed-in. PV plants with outputs of between 30 and 100 kW must be equipped with a simple feed-in management system, with a device that reduces feed-in capacity being sufficient. Operators of PV plants with outputs of less than 30 kW have the choice of either us-ing a simple feed-in management system or limiting the feed-in capacity at the grid connection point to 70% of the maximum module output. This means that peak power outputs are capped at a fixed rate. Regardless of their outputs, existing plants have to be suitably upgraded in case the generator’s rated output exceeds 30 kWp.

Static grid support is required when grid voltage rises or falls slowly. Support is provided by supplying reactive power and limiting active power dependent on the frequency. Dynamic grid support is predominantly required when voltage dips occur in the upstream high-voltage grid. The PV plant should not then shut down immediately, but should remain on the grid for a time (fault ride through, FRT) and feed-in reactive current to sup-port the grid voltage dynamically. Only when the grid ceases to function for sev-eral seconds is the PV plant shut down for safety reasons.

Data loggers, which in addition to mea-suring grid parameters, control real pow-er and feed-in reactive power where nec-essary, have recently been put to use to support grid services. They enable ripple control receivers to be connected and log the resulting reduction in power. Man-ufacturer-independent monitoring de-vices are another way of monitoring and analyzing the various inverters within a plant.

The VDE-AR-N 4105 is also intended to contribute to avoiding frequency sta-bility problems in the power grid. For example, it states that, in future, photo-voltaic installations will not strictly need to be completely disconnected from the grid upon reaching an overfrequency of 50.2 Hz, but rather that there will be a smooth transitional zone between 50.2 Hz and 51.5 Hz, within which the in-stallation may continue to feed in power at a reduced capacity. This new applica-tion guide also affects existing plants with outputs of over 10 kWp, which need to be upgraded accordingly. The different

00

Time (s) Time (s)0 0.040.02 0 0.040.02 0 0.40.2Time (s)

Voltage

Possible grid disturbances

Some power supplies, such as those used in older computers but also in other recent appliances and compact fluorescent light bulbs, cause changes in sine waves.

When “capacitive” power appliances are switched on, brief disturbances arise. Battery chargers are examples of capacitive loads. But these loads have to be very great indeed for the disturbances to have an impact.

A large power consumer can put such a great load on the grid that voltage drops. Inverters can only compensate for such disturbances if the devices can store electricity.


26

cut-off frequencies of individual invert-ers are distributed stochastically in such a way that all inverters synchronize with the cut-off point of one single inverter.

Since July 1, 2011, static grid support will be prescribed by law in Germany. This applies to all inverters that feed into the medium and low voltage grids which have an out-put of 3.68 kVA or above (230 V x 16 amps, A). The transitional period expired on January 1, 2012, so practically all PV plants that are connected to the grid will be re-quired to perform this grid service. These increased requirements on systems tech-nology – particularly inverters – contrib-ute to stabilizing the power grid and bring with them the advantage that it will now be possible, even in weak grids, to install a far greater amount of PV capacity before expansion of the grid is required.

VDE AR-N 4105 also aims to improve load balance, as this can become unbalanced during single-phase feed-in from a mul-titude of power generators. There is now an unbalanced load limit of 4.6 kVA per phase in place, even in the event of faults. Only a maximum of 13.6 kVA per PV plant can be connected to the grid with three single-phase feed-in inverters. As a result, three-phase feed-in inverters are increas-ingly being used.

Using power from a low-voltage grid of-fers great potential for conserving and displacing power, which can be opti-mized by decentralized feed-in systems. Micro grids generating their own power, which are connected to one another by

the public grid, can play a decisive role in this and can complement the grid inte-gration of photovoltaic systems. It is also intended to encourage on-site consump-tion (for roof-mounted installations of up to 500 kWp).

Decentralization and consumption at source

Using intelligent control engineering, a variable, virtual, large-scale power sta-tion could be developed in connection with decentralized feed-in systems and electricity consumers. As elements in this power plant, PV plants would contribute to reducing the purchase of electricity from the public grid. Moreover, PV plants could improve supply security through short-term island operation.

In future, inverters will take over more and more grid management tasks and provide energy services. In addition to stabilizing voltage and frequency, these include controlling the power factor and the targeted production of harmonic components to improve grid quality. For this reason, bidirectional network inter-faces are required to enable the neces-sary communication and to link the large number of decentralized suppliers and consumers together in “smart grids”.

Due to the decentralized nature of solar power generation, it is obvious that users generating power should themselves con-sume as much of this as possible at source. This reduces grid feed-in and the need to transport power over great distances.

In an average household, 20-30% of en-ergy is consumed at times when solar power is generated. Simple measures could be used to increase this proportion by a further ten percentage points, for example by logging consumption as well as generation using the automatic plant monitoring system, which will compare both graphically. Users could then bet-ter adapt their consumption to match generation and maximize their own con-sumption of the solar power.

With an energy manager, the inverter could be fitted out so that it automati-cally switches on individual household appliances (washing machines, dish-washers, tumble dryers, etc.) as soon as enough solar power is generated. These appliances would be equipped with remote-controlled sockets and their performance data stored as profiles. The PV plant and the power network in the home would thus be unified, and elec-tronic appliances would be supplied with either pure solar power or a mix of solar and grid power depending on insolation.

In Germany, the on-site consumption of solar power was subsidized as part of the Renewable Energy Sources Act (EEG) between January 2009 and March 2012. Only energy consumed concurrently with its production, i. e. the actual energy that was not fed into the grid but was directly consumed in close proximity to the PV plant, was considered to be for “own con-sumption”. It was not possible to balance out yield produced throughout the year with annual consumption. In order to

The power grid comprises different voltage levels. Overland transmission lines work at extra-high voltage but this voltage level is reduced from high to medium and finally low voltage as the power is transported to consumers. In the past, power was only ever transmitted in one direction from centralized (large-scale)

power plants to (decentralized) consumers. Due to the decentralized production of renewable energy, however, the flow of current can reverse and the power grid needs to be appropriately prepared for this. By feeding in reactive power, PV power plants are able to contribute to grid stabilization.


Voltage levels in the German power grid

UlTRA-HIGH VOlTAGE 380/220 kV

HIGH VOlTAGE 110 kV

MEDIUM VOlTAGE 20 kV

lOW VOlTAGE 0.4 kV

Transformer substation



Consumers:Towns, cities and

communities

Consumer:Industy

27

check concurrency, a production meter was required in addition to a reference and feed-in meter. The actual on-site con-sumption was calculated from the differ-ence between production and feed-in. In the current version of the EEG, the on-site consumption bonus has been removed and feed-in tariffs for solar energy have plummeted to such low levels that in many cases remuneration is lower than the net price for purchasing electricity. Even without subsidies, this makes the on-site consumption of power worth-while.

If feed-in is single-phase but individual consumers have a three-phase connec-tion, differences will arise which impact badly on the evaluations of own con-sumption. Three-phase feed-in is, there-fore, an advantage.

The next step is to bring together energy consumption control and battery stor-age – either as a stationary battery bank or in mobile format in an electric vehicle. Conventional batteries are only of limited suitability for this purpose because high storage losses and low efficiency lead to costs of 20 to 30 euro cents per kilowatt hour saved. These costs can be reduced by higher consumption of energy at source, improved load displacement and, above all, by increased conservation.

A view on the United States

Solar electricity, though making up only a small fraction of the USA’s power gen-eration, is cementing its place as a long-term source of energy. With this progress comes the need to re-imagine the future of the electric grid. In the United States, many utilities and grid operators are do-ing just that as they grapple with scenari-os that will require a more dynamic act of balancing the supply and demand.

California presents the best case study. Eleven years after California established a renewable energy generation goal and set an example for the rest of the coun-try, the state is just now starting to see a large infusion of solar energy going into its grid. In regulations and policy planning, the state’s utilities and the grid operator, the California Independ-ent System Operator, have been carrying out studies and technology trials to fig-ure out how to manage the grid when it gets a big surge of solar energy for part of the day and when solar power plants go offline because of cloud cover. The use of energy storage could help even out the power flow.

Integrating more advanced functions into inverters, on the other hand, is now a key way to help manage the growing amount of solar energy in the grid. Func-tions such as low-voltage ride through, reactive power injection, over-frequency response and ramp-up control are either required or considered for interconnect-ing solar power projects in the transmis-sion and distribution networks.

These functions, while not new in their existence, are new in the United States because the country is a younger solar energy market. According to GTM Re-search, preliminary data show that by the end of 2012, the country reached a cumulative PV installation of 7.1 DC GW. This number is small compared to what Germany could install in one year.

According to the largest utility in Cali-fornia, penetration is currently low and the units do not have significant impact on the system so interconnection can be made relatively easily. But at a high dis-tributed generation penetration, and for large units, the distributed generation im-pact may be much higher and/or the grid may not have sufficient operating margin to cover for the renewables if a large num-ber of them tripped off unnecessarily due to a major system disturbance.

Several large solar power plants are un-der construction in the western USA that will start to drive up the solar content of the electric grid, most notably in Califor-nia. The country had 2.1 DC GW of utility solar projects under operation at the end of the third quarter of 2012. GTM said that there was another 10 DC GW that were under contracts with utilities but had not been built.

PHO

TO: PU

GET SO

UN

D EN

ERGY

PHO

TO: FIRST SO

LAR

As one of the first utility-scale PV projects in the United States, the 21 MW Blythe Solar Power Project in California includes 350,000 thin-film modules. It serves the needs of approximately 6,000 local homes.

Maintenance work on transmission lines in the USA


28

Large-scale solar development is happen-ing mostly in the western USA, particu-larly in California, Arizona and Nevada. This includes a 250 AC megawatts (MW) project in San Luis Obispo County in cen-tral California, and that project is close to another 550 AC MW solar farm. Two power plants totaling 579 AC MW are being built in southern California, and in Arizona a 290 MW project is under con-struction.

Advanced features

An inverter’s core job is to convert the DC from solar cells into AC, but increasingly they are now expected to monitor the grid’s heath closely and react accordingly.

The Institute of Electrical and Electronics Engineers (IEEE) has undertaken the task of modifying the 1547 standard for inter-connecting renewable energy generation with the electric grid. Standard setting is a long, multi-year process, and efforts are underway to speed up the process for connecting PV generation systems given PV technology has surged ahead of other solar technologies to dominate the market. Voltage and frequency regu-lations are the two big issues for keep-ing the grid working properly. The grid in the USA operates at 60 Hz. Transmission lines generally run from 138 kilovolts (kV) to 765 kV, whereas distribution lines run to 4 kV.

The IEEE 1547 participants have been look-ing at whether to mandate certain tech-nologies for voltage and frequency regu-lations, the jobs of which would or could then fall on the inverters. Until now, tech-nical standards have largely focused on making interconnection fairly easy and inexpensive, given the low saturation of solar energy in the grid. As solar increases its share of the power mix, however, more sophisticated control of its impact on the grid will be needed. One of the more ad-vanced inverter features, low-voltage ride through, seems certain to be included as part of IEEE 1547 to deal with the effect of a greater amount of solar power flow-ing into the grid. The function keeps the inverters pumping solar power into the grid even when the voltage of the grid drops and becomes instable. The idea is not to shut off all the PV systems when the voltage dips because, according to micro inverter developers, doing so is not necessary and may contribute to more instability of the grid. If a large amount of solar energy production goes off line unexpectedly, then the utilities will have to scramble to make up for the shortfall, or else they risk a blackout.

Low-voltage ride through does some-what conflict with an existing IEEE 1547 requirement that all inverters are turned off automatically when they detect cer-tain voltage or frequency levels that de-viate from the norm. Resolving the dif-ferences in these two functions will be needed in the standard-setting process.

While the IEEE 1547 process moves for-ward, some grid operators and utilities have already adopted the low-voltage ride through function for PV systems as requirement it for transmission line interconnection, for example. The Cali-fornia Independent System Operator, for example, requires it for transmission line interconnection. Meanwhile, one of the largest utilities in the United States based in San Francisco, uses inverters with low-voltage ride through capability in its own PV power projects connected to its distribution network.

Reactive power injection is another func-tion that helps to keep the grid humming along. Its presence is necessary to keep the voltage at desirable levels in order to deliver active power – energy measured kilowatt hours – through transmission and distribution lines efficiently. Utili-ties typically use a bank of capacitors to supply reactive power, measured in volt-ampere reactive (VAR), to keep the volt-age level up when a big load of power is brought online.

Inverters can provide reactive power injec-tion, too, and usually through the point of interconnection, though solar power plant owners do not really have an incentive to do so. That is because utilities do not usu-ally pay for reactive power in the power purchase agreements they sign with solar power project developers. If a solar farm is sending reactive power, then it is not feed-ing active power into the grid. Although compensation is a big issue, some devel-opers could still offer reactive power injec-tion as a way to hopefully speed up their interconnection agreement negotiations with utilities.

PHO

TO: FIRST SO

LAR

Nearly 775,000 thin-film PV panels were installed for the 48 MW

Copper Mountain Solar plant in Nevada, USA. The facility generates electricity to power

about 14,000 average homes.


29

Inverters also can provide over-frequency response by dialing back the injection of active power to bring the frequency back to the ideal 60 Hz.

And increasingly, power plant developers are asking for ramp-up control. The ramp-up function is designed to gradually bring the solar power plant online. Power plants in general have a ramp-up process to increase their output until they reach full production. This process needs spe-cial monitoring and control with a solar power plant because solar power produc-tion is not as steady as a fossil fuel power plant. While adding the ramp-up control to inverters is not a difficult task, creating the ramp-down control is much harder. The use of energy storage to accompany the ramp-down process would be neces-sary, and that adds additional cost.

Making them work for a complex grid

Adopting more advanced inverter tech-nologies will be more challenging in the United States than in countries such as Germany, which is not only smaller but also has a national solar policy and grid management system. The United States, on the other hand, has a far more com-plex electric grid and over 3,200 utilities. In fact, the grid in the continental USA is composed of three regional grids that are overseen by eight regional grid reliability organizations and one national group, the North American Electric Reliability Corporation.

That complexity makes it difficult to set technical standards and mandate consistent best practices nationwide to manage the growing solar power gen-eration. Making sure any standards leave room for configuring inverters to fit the needs of grid operators and utilities is key. At the same time, adding more inverter functions will also make solar power pro-jects and grid operations more complex and costly. Currently, there are national standards to make sure inverters from different manufacturers can communi-cate and work well with one another and with the equipment a utility would use to manage the grid.

In order to utilize the more advanced features, the distribution system will be-come much more complicated in design. Costs and benefits of implementing the additional features are also needed to be weighed.

PHO

TO: SIEM

ENS A

G

Installation of a power converter valve module for use in a high voltage direct current (HVDC) transmission system

PHO

TOS: SIEM

ENS A

G

The grids of the future are set to be smart: Intelligent technology ensures that energy systems are equipped with information and communication technology to control the feed-in of decentrally generated energy.


30

Storage and Energy ManagementThe development of efficient power storage systems with high lifespans is essential for photovoltaics to be-come a stable mainstay of electricity generation in spite of seasonal fluctuations in the amount of solar power generated. The effects of short-term fluctuations from one hour to the next are lessened by load shifting and solar heating. Meanwhile, decentralized energy management is gaining in importance as much as decentral-ized power production. To ease the burden on the grid, as much solar power as possible should be consumed on site or in the immediate vicinity of the location in which it is generated.

An intelligent management system for battery power plants is indispensable for integrating storage systems into both private and large public grids.

PHO

TO: TO

M BA

ERWA

LD/YO

UN

ICO

S TECH

NO

LOG

IEzENTRU

M

Storage and Energy Management

31

Surpluses persist despite on-site consumption

Photovoltaics can only generate power during the day and yields are significant-ly higher in the summer. In order for PV plants to make a considerable contribu-tion to the power supply, the further in-crease in solar power generated must be underpinned by an expansion in storage capacity. As the daily and seasonal fluc-tuations in output are each compensated for by different forms of storage, a two-pronged approach, comprising a mixture of small, decentralized short-term stor-age systems and large seasonal storage systems, is required to extend storage capacities. Differentiation must also be made between storage systems that maximize benefit for plant operators (i. e. systems that are charged when the solar power cannot be consumed immediately on site) and those which are beneficial to grid operators (i. e. systems that are only charged when there is a surplus of power in the grid).

Due to the relatively high costs of storing power, it is vital that as much as possible is consumed immediately and decentral-ly. This means that the importance of on-site consumption will continue to grow.

The on-site consumption of solar power was subsidized in Germany between January 2009 and April 2012. The strong growth of photovoltaics in Germany has now led to a situation where excess so-lar power is produced in some regions during the middle of the day. Power generation is becoming regionally con-centrated during specific periods. Given that, in most cases, the power supplied by the PV plants dramatically exceeds the demand of nearby consumers, it is impossible to avoid creating such a sur-plus simply by introducing provisions for on-site consumption. As the number of new PV installations increases year on year, the number of regions where more solar power is generated than consumed is also set to rise.

Subsidizing storage

In Germany, solar power storage sys-tems are set to be subsidized by an investment grant. It has been report-ed that in order to receive funds, the storage systems must contribute to easing pressure on the grid, especial-ly that created by solar power pro-duction. Grants of between 2,000 and 3,000 euros per storage system are anticipated and a total of 50 mil-lion euros is set to be made available for the subsidies. The exact date of the introduction is yet to be decided (as of March 2013).

PHO

TO: TO

M BA

ERWA

LD/BA

E BATTERIEN G

MB

H

Lead-acid gel battery

PHO

TO: TO

M BA

ERWA

LD/YO

UN

ICO

S TECH

NO

LOG

IEzENTRU

M

Simulating sudden drops in load, short circuits or changes in the weather ensures that storage

systems are also able to function safely in extreme conditions.


32

Storage media

The portion of solar power that can nei-ther be absorbed by the grid nor used directly on site needs to be temporar-ily stored. Batteries are the primary con-tenders for this task, as they have proven their worth over decades of use and can be employed in decentralized systems. Owing to topographical restrictions in Germany, cross-regional storage in res-ervoirs (pumped storage hydroelectric power stations) is only possible to a very limited degree. Compressed air energy storage represents one alternative tech-nology that, in principle, holds great po-tential, but its efficiency is still in need of improvement.

Converting solar power into chemical en-ergy (e.g. by means of electrochemical hy-drogen generation) incurs relatively high losses, but does bring with it the advan-tage that energy can be stored for long periods of time. Solar hydrogen can be converted into either electricity or heat and can also be used as fuel, directly sub-stituting petroleum products. Converting hydrogen into methane would achieve an even higher energy density and thus tap into an even greater storage capacity. In this case, the efficiency of converting the energy does drop somewhat, but this would still be acceptable given that free sunlight is the energy’s source.

0 0 1 2 3 4 6 7 0 0 1 2 3 4 6 7

Source: Volker Quaschning, Regenerative Energiesysteme, 7th edition, Hanser Verlag, Munich2011

I. II.

III.

IV.

1.

2.3. 4.

5. 6.

7. 8.

Potential use of solar power in private households

5. Consumption meter6. Feed-in meter7. Energy utility8. Power grid

1. Solar installation2. Energy management3. Consumption devices4. Storage system (battery)

In view of the steadily falling feed-in tariffs, it is becoming increasingly important for installa-

tion owners to consume as much solar power as possible in their own homes. On-site consump-

tion (I.), which can be increased by means of load shifting, takes precedence over storage (II.), as this

entails relatively large losses. Solar power is only fed into the grid when the battery is fully charged

and the consumption devices do not require power (III.). Purchasing

relatively expensive electricity from the grid (IV.) is the least favorable option, and should only be considered if the PV installation is supplying too

little power and the battery is run down.

The latest developments in technology do not allow us to foresee which storage systems will triumph in the long term. The most likely scenario will involve a mixture of small, distributed, short-term storage systems and large, seasonal stor-age systems. Ultimately, if the intention is to make photovoltaics a mainstay of German power supply, a solution must be found to store the surpluses generated in summer for use during winter.

SOU

RCE: zEN

TRUM

FüR SO

NN

ENEN

ERGIE- U

ND

WA

SSERSTOFF-FO

RSCH

UN

G BA

DEN

-Wü

RTTEMB

ERG (zSW

)


Storage duration and storage capacity

1 year

1 month

1 day

1 hour

1 kWh

10 kWh

100 kWh

1 MWh

10 MWh

100 MWh

1 GWh

10 GWh

100 GWh

1 TWh

10 TWh

100 TWh

Batteries

Compressed air energy storageCompressed air energy storageCompressed air energy storage

Pumped storage power plants

Hydrogen Synthetically produced methane

Several storage technologies are needed to compensate for fluctuations in the amount of solar

power generated. Small quantities of power are stored in batteries in the short term, while large quantities are stored in the form of hydrogen or

methane in the long term.

33

Batteries

The only type of instant storage currently available is that of secondary electro-chemical cells, generally known as (re-chargeable) batteries. However, the un-avoidable phenomenon of self-discharge in batteries means that they are only suited to storing solar power for short (from a few hours to a few days) and me-dium (a few weeks) periods.

Moreover, the lifespan of a battery is lim-ited by its cycle life, not forgetting that the number of possible charge cycles falls as the depth of discharge increases. The battery therefore needs to be protected against over-discharge. In lead-acid stor-age batteries, for example, full discharge converts the lead sulfate into a crystalline form which is only partly dissolved when the battery is charged again, causing per-manent damage.

What is more, the capacity that can be extracted from an accumulator decreas-es as the discharge current becomes more powerful.

Lead-acid storage batteries are cheapest and are therefore most frequently used. They are filled with an electrolyte of di-lute sulfuric acid, meaning that if the fi-nal charge voltage is exceeded, gassing may occur. When this happens, oxygen forms on the positive electrode and hy-drogen on the negative. These two gases then form explosive oxyhydrogen. Gas-sing also leads to the gradual loss of wa-ter, which needs to be regularly refilled. Overall, the cycle life of lead-acid storage batteries is relatively low.

In order to increase its lifespan, the elec-trolyte can be thickened using additives to form a gel. Lead-acid gel batteries can be assembled fully sealed, meaning that they are leak proof. In this case no gas is able to escape, but lead-acid gel batter-ies may dry out as a result of gassing. A special charge controller is therefore nec-essary to manage the final charge volt-age very precisely. Lead-acid gel batter-ies have double the lifespan of lead-acid storage batteries with liquid electrolytes. They allow around 2,000 cycles, provided no more than 30% of the capacity is dis-charged each time. If 50% of the capacity is drawn on a regular basis, lead-acid gel batteries will need to be changed after around just 1,000 cycles.

Lithium-ion batteries achieve markedly higher cycle lives. If discharged and re-charged daily, they can reach a lifespan of 20 years, equating to 7,000 charge cy-cles. Their special features include high energy densities and low self-discharge rates. They also withstand high charging currents, and can therefore be charged very quickly. These advantages currently make them ideal storage batteries for homes and electric cars. Prices for such batteries are still high, however, and will not fall until mass production levels are achieved.

Redox flow batteries

Both types of storage battery (lead-acid and lithium-ion) share the common feature that their electrodes undergo chemical conversion during charging and discharging, and therefore slowly degen-erate. Redox flow batteries avoid this. A relatively new development, these bat-teries combine the properties of the ac-cumulator with those of the fuel cell.

The reactants are each dissolved in an electrolyte and circulate separately. These two electrolytes are pumped through a cell in which ions are exchanged. This cell is divided by a membrane that only allows ions to pass through it, thus pre-venting the reactants becoming mixed.

The electrolytes that store energy in re-dox flow batteries are kept in separate tanks. As a result, the quantity of energy and the output can be scaled indepen-dently of one another. Redox flow bat-teries are characterized by their high ef-ficiency and long life expectancy.

The capacity of the redox flow stor-age systems that are shortly due to be launched on the market lies between 3 and 13 kWh. Apartment buildings and commercial establishments require larg-er units, providing an opening for those redox flow batteries that are currently offered in 200 kWh modules. Here, addi-tional modules can be added to increase the capacity.

As both lithium-ion batteries and redox flow batteries are still at an early stage of development and are relatively expen-sive, the lead-acid battery is still the most economical way to store solar power, de-spite its short cycle life.

During charging, the graphite absorbs electrons, while the metal oxide at the battery’s other pole releases electrons into the external power circuit. In doing so, lithium ions flow from left to right (,) and settle between the layers of carbon. The entire process is reversed during discharging (%). While the separator is permeable to the lithium ions, it does not allow the negatively charged counter-ions to pass through it, thereby preventing self-discharge. The graphite and metal oxide electrodes are often made in the form of foil. An electrolyte is placed between them, through which the lithium ions are able to flow.

Lithium-ion batteries come in many forms, which vary in terms of the materials used to make the electrodes, separator and electrolyte.

lithium-ion battery

+

Al

-

Cu

CHARGE

DISCHARGE

li+

li+

li+

li+

lithium Oxygen Metal (cobalt, nickel, manganese)

Carbon Electron Separator


34

Storage systems

Overall, storing solar power in batteries is a relatively expensive enterprise. It cur-rently costs roughly as much to store a kilowatt hour of electricity as it does to generate it from sunlight. The specific costs of storage (in euro cents/kWh) are not the sole criterion, however. If the goal is to operate a battery system as profit-ably as possible, cycle life, the output of the PV plant and household energy re-quirements must also be considered.

In order to incorporate batteries into a PV system, special storage systems are required which consolidate the stor-age battery with the necessary power electronics. These have only recently be-come available on the market. They not only differ according to battery type, but also based on how they are installed. Some systems are incorporated into the house’s AC circuit, while others are inte-grated into the PV plant’s DC circuit.

Integrating the system into the AC circuit has the advantage that as much addi-tional capacity as desired can be added at a later date, irrespective of the PV capac-ity installed. A battery inverter is needed in addition to the PV inverter, meaning that relatively high outlay is required, but such systems come with the extra advan-tage that power from the grid can be fed into them more easily, as the battery in-verter operates bidirectionally.

Incorporation into the DC circuit also has two advantages: the system costs are lower and the storage efficiency is higher. This method requires the installation of a PV inverter and a pair of DC/DC con-

verters. They set the voltages of the PV system and the battery at precisely the level that is best for the inverter. To sim-plify matters, they can be installed in the metal cabinet that houses the battery.

Despite the high investment costs in-volved, battery capacity should be se-lected to enable as much solar power as possible to be consumed on site. By way of example, for a 4 kW plant and annual energy consumption of 4,000 kWh, a ca-pacity of 6 to 7 kWh is recommended if the quota of on-site consumption is in-tended to reach 70%. A quota of over 30% will be virtually impossible to achieve without using storage, unless the solar power is also used to heat water. Com-binations of photovoltaics, heat pumps for water heating and intelligent energy management, for instance, can achieve on-site solar power consumption rates of up to 50%, even without storage systems. Of course, checks should always be made to examine whether or not solar thermal installations will represent the most eco-nomical solution for the actual needs and conditions of the site.

Maximizing on-site consumption with-out considering the consequences must, however, be avoided. Care must always be taken to ensure that consumption only increases in order to raise the quota of on-site consumption and that power is not used arbitrarily and unnecessarily, as this would be counterproductive in terms of energy efficiency. On the other hand, replacing fuel, by, for example, us-ing energy-saving electric vehicles on a large scale, would be a highly welcome development.

Heat accumulators and heat pumps

One very simple way of storing energy is to store heat. As buffer storage is already available in some houses in the form of hot water tanks, surplus solar power could also be converted into heat by con-ducting it through an immersion heater inserted into the storage tank. As long as the production of solar power is signifi-cantly more expensive than producing hot water, this will remain a very waste-ful use of energy. Nevertheless, falling solar energy generation costs combined with rising prices for raw materials will slowly close this gap.

A far more efficient application of sur-plus solar energy is in a heat pump. If this pump is capable of generating 3 kWh of heat from 1 kWh of electricity, 1,600 kWh should theoretically be sufficient to heat a well-insulated house with a living area of 120 m2 and heating requirements of 40 kWh/m2. This calculation is unrealistic, however, as supply and demand do not coincide: In winter, when the greatest de-mand is placed on the heat pump, the PV plant will furnish the least electricity.

DC and AC storage system

AC COnnECTED PV BATTERY

SYSTEMS

Public grid

Bidirectional meter

Production meter

InVERTER

DC COnVERTER

CHARGE REGUlATOR

123456123456

123456

ConsumerSolar installation

Battery

=

~~==

==

Public gridBidirectional meter

Production meter

InVERTER

DC COnVERTER

123456123456

123456

ConsumerSolar installation

Battery

=

~~==

CHARGE REGUlATOR

==

BATTERY InVERTER

~~=

DC COnnECTED PV BATTERY

SYSTEMS

In an AC system, the battery is sepa-rately connected to a house’s alternating current grid via an inverter and direct current converter.

In a DC system, the battery is connected between a direct current converter and the original

inverter.

A fundamental decision when choosing between storage concepts is whether to use a DC- or

AC-connected system. An intelligent measuring system is needed to record the quantities of power

which are generated, stored, consumed on site or fed into the grid.

A production meter is only required for DC-connected systems where it is necessary to

prove the quantity of solar energy generated, e.g. in the event of bonuses for on-site consumption

or partial remuneration. AC systems may be required to be fitted with a

meter (not shown) attached to the battery system showing that it feeds solar power into the grid

instead of charging its battery using grid power.

( (


35

The conditions are somewhat different if the heat pump is used to provide cooling via an air-conditioning unit. In this case, the periods of energy production and consumption do correlate if power from the photovoltaic plant supplies electric-ity for heat pump cooling during the summer months. In the USA, for example, heat pump cooling is already widespread.

Irrespective of their intended use, heat pumps are not suitable for storing energy over the long term, but merely represent a component of good energy manage-ment.

Energy management

It is considerably easier to generate solar power than to store it, as this entails rela-tively complex installation procedures and unavoidable losses. In order to com-plement the storage options, as much energy as possible must therefore be consumed on site and the conditions for marketing the power must be made as favorable as possible. This situation will then replace the current practice of unre-servedly feeding power straight into the grid. If the statutory feed-in tariffs were to be abolished, or sink so low that it be-came unviable to feed all the solar power generated into the grid, this custom would die away. Grid feed-in will then only be sensible under certain circum-stances and should only be considered if other options are not available.

Load shifting can help to increase on-site consumption rates. For example, large household devices that do not require power at a given time might only be switched on when solar power is in plen-tiful supply. Washing machines, tumble driers and freezers can thus contribute to improving the coordination between de-mand for power and supply. These energy management systems need to succeed in changing the consumption patterns of the average consumer, i.e. to drive them away from simply using household pow-er at any time at the push of a button. They must clearly indicate the costs per

kilowatt for each device at a given mo-ment and ideally offer alternative oper-ating times within the shortest possible time frame.

Favorable sales conditions will become possible if the tariff for purchasing pow-er from the grid increases while the solar power produced on house roofs becomes cheaper at the same time. This power can then be sold to neighbors in close distance at a price below the electricity tariff, as the short distances will mean that grid fees are waived.

Only once these two channels have been exhausted should solar power be used in hot water tanks or heat pumps. Using solar power for heating means using so-lar energy under its value. This is why it ranks third in the hierarchy of solar pow-er exploitation.

Given the fact that storing power in bat-teries will remain relatively expensive for the foreseeable future, it should be avoid-ed if at all possible. If several other pos-sibilities for use are in place, only a small battery capacity will be required.

As a last resort, feeding power into the grid remains an option. This would strug-gle to contribute to PV plant profitability, however, as solar surpluses are produced by many PV installations simultaneously.

Increasing on-site consumption through load shifting and solar heating, selling power, storing it, and feeding it into the grid are the options available to the en-ergy management systems of the future. If possible, these systems should be able to independently decide on which type of use would be most beneficial to PV plant profitability at which times, and to activate consumption devices and stor-age systems as required. This concept demands a great deal of the systems technology, which will inevitably change over time. Gradually inverters will be re-placed by energy management systems. Developing these is the task that now lies ahead.

0 0 1 2 3 4 6 7 0 0 1 2 3 4 6 7

Source: Volker Quaschning, Regenerative Energiesysteme, 7th edition, Hanser Verlag Munich 2011

I. II.III.

1.

2. 4.

6.

7.

5.

3.

8. 9.

10. 11.

Photovoltaic back-up heating

1. Solar installation2. Energy management3. Consumption devices4. Heat pump5. Combi heat storage tank6. Shower7. Heating system8. Consumption meter9. Feed-in meter

10. Energy utility11. Power grid

As solar power generation becomes increasingly less expensive, it may be practical to utilize this power not only to operate household devices (I.), but also to back up the heating system (II.). Surplus power can then be fed into the grid (III.). However, since

remuneration for this is becoming ever lower, the option of producers marketing their own electricity and thus creating a distributed power supply is fast

developing – but this requires an appropriate legisla-tive framework.

PHO

TO: TO

M BA

ERWA

LD/B

OSC

H-PO

WER-TEC

H

Inverter system with an integrated energy manage-ment system for optimizing on-site consumption


36

Power storage has always been a key requirement to achieving self-sufficient energy supply in locations situated away from the grid. Short-term power fluctua-tions, caused for example by clouds pass-ing overhead, have particularly negative effects on these stand-alone systems and appropriate storage capacity must be made available to counterbalance this. For instance, batteries capable of storing 250 kW are required to compen-sate for unexpected power fluctuations in solar plants with outputs of 1 MW. The batteries used must also be capable of discharging quickly. Lithium-ion batter-ies, and in particular those with medium energy densities, have been found to be highly suitable for this.

The solar power supply of stand-alone systems therefore makes additional de-mands on energy management. Load shifting plays a vital role in this area.

Storage costs

Outlays for storage are determined by the system’s investment costs and life-span. When calculating these, focus is placed on the capacity-related costs (euros/kWh) as opposed to the perfor-mance-related costs (euros/kW), with the efficiency of the battery system also playing a role.

The lifespan of batteries used to store solar power should ideally be at least as long as that of PV plants, i.e. 20 years. The desired lifespan of the first mass produced batteries is ten years. Traction batteries, which are currently being de-veloped at breakneck speed for the au-tomotive industry, have much shorter lifespans of between five and eight years, making them less suitable for storing so-lar power. What’s more, they remain too expensive. A lithium battery currently costs around 400 euros/kWh. Although this amount could fall by half over the next five years, lithium batteries would still remain more expensive than their lead counterparts. A way of overcoming this problem would be to combine large lead batteries with small lithium-ion batteries. To protect lead batteries from peaks in demand, which could result in damaging over-discharge, lithium-ion batteries should be employed during peaks in demand, while lead batteries should be used to cover base load.

As the cost of storage falls with increas-ing lifespans, a battery’s cycle life is of great significance. Taking into consid-eration the levels of insolation normally seen in Germany, batteries need to be charged and discharged around 3,000 to 4,000 times in the space of 20 years. Lith-ium-ion batteries have already achieved a cycle life of this extent. Lead batter-ies, on the other hand, are only capable of performing around 1,000 cycles, out-weighing the advantage of their lower investment costs – unless, of course, they are combined with lithium batteries (see above).

Overall, the drop in prices brought about by the technical development of storage media and the economies of scale result-ing from mass production, as well as the coordinated interplay between the vari-ous forms of storage, shall contribute to ensuring that the share of photovoltaics in the power supply continues to grow.

PHO

TO: N

ExT EN

ERGY

Development of new battery systems: initial tests in a research lab

PHO

TO: TO

M BA

ERWA

LD/H

OPPEC

KE BATTERIEN

GM

BH

& C

O. KG

Lead-acid batteries with dilute sulfuric acid acting as a liquid electrolyte


37

Plant Monitoring and Identifying FaultsEvery kilowatt hour counts, because only kilowatt hours that are fed into the grid or privately consumed are remunerated. It is therefore necessary to thoroughly monitor operational data. A plant’s operator can only take prompt measures to eliminate operational faults and failures where these are signaled immediately. Merely reading the feed-in meter each month is not sufficient to recognize faults promptly and to avoid the loss of yields. Constant measurements are therefore necessary to ensure optimal operation.

PHO

TO: TO

M BA

ERWA

LD/LEB

HERz

Plant monitoring using thermal imaging

Plant Monitoring and Identifying Faults

38

Constant measurements are essential

Many inverters record the most impor-tant operational data, evaluate the data automatically and, in the event of a fault, send the operator notifications via email, text message or internet. This is sufficient for basic plant monitoring. However, it only allows obvious faults, such as fault currents or total failure, to be recorded.

In order to determine whether a PV plant is producing optimal yields, the plant data needs to be measured continually, and preferably compared with the actual radiation values present. This is due to the fact that currents and voltages, and consequently feed-in capacities, con-stantly change depending on meteoro-logical conditions. The operator can only determine whether or not the PV plant’s operational data indicate optimal func-tioning by directly comparing them with insolation data.

Measuring insolation and output

Solar radiation is measured using either pyranometers or PV sensors (reference cells). A third – more indirect – possibil-ity is to compare a plant’s data with me-teorological information and yields from PV plants in the vicinity.

Pyranometers measure insolation with great accuracy. They essentially consist of one or two hemispherical glass domes, a black platelet that acts as an absorbing surface, the thermal elements positioned below this and a metal casing. Solar ra-diation heats the absorbing surface, the warming of which is directly dependent on the insolation. Insolation can thus be

ascertained from the temperature differ-ence between the absorbing surface and the white metal casing. Pyranometers are installed horizontally when meteoro-logical data is needed and in the module plane when PV output requires monitor-ing.The advantage of high measuring ac-curacy is, nevertheless, opposed by a seri-ous disadvantage: Due to their thermal functionality, pyranometers are relatively sluggish, which means that they are inca-pable of accurately detecting rapid inso-lation fluctuations caused, for example, by scattered clouds.

PV sensors, which are also installed in the module plane so that they are exposed to the same insolation conditions as the modules, provide a cost-effective alterna-tive to the accurate, but slow and expen-sive, pyranometers. A PV sensor consists of a solar cell which supplies power in proportion to insolation. This power is, however, also dependent on the operating temperature of the solar cell, which means that a temperature sensor is necessary in order to offset thermal effects and deter-mine the exact insolation. However, owing to its limited spectral response, the solar cell cannot detect certain portions of the insolation, and reflection losses may also occur. PV sensors are therefore much less accurate in their measurements of insola-tion than pyranometers. Despite this, they are often used to monitor PV plants. This is because a PV sensor can be selected to correspond to a plant’s modules. For exam-ple, a PV plant consisting of CI/GS/Se thin-film modules is monitored by a PV sensor with a CI/GS/Se solar cell. This simplifies the comparison of instantaneous values, which means that operational faults and defects can be recognized quickly.

Like silicon-based PV sensors, pyranome-ters measure absolute insolation in watts per square meter (W/m2). Thanks to their technological differences, however, they are capable of recording slightly differ-ent solar spectrums (while silicon cells’ restricted spectral response means they are only able to perceive the “silicon spec-trum”, pyranometers are able to register the entire solar spectrum). Consequently, when measuring global irradiation, pyra-nometers invariably record higher levels of insolation than silicon sensors, and, conversely, lower performance ratio (PR) values, as a result of global insolation being used to calculate the denomina-tor of the PR formula. When exposed to the same level of insolation, modules produce a greater output on a cooler day than on a warm day, meaning that it may be necessary to measure the operating temperature of the modules in order to determine the exact output.

Comparisons with regional meteorologi-cal data mean that pyranometers and PV sensors are no longer required. Yield simu-lations are calculated using data supplied by neighboring meteorological offices and compared with the actual yield. Operators can also check their own performance data by examining the yield of nearby PV plants. Both methods have the disadvan-tage that faults often go unrecognized for hours or even days. Furthermore, the validity of this comparison is limited by regional differences such as cloud cover or vegetation. A rule of thumb is that a PV plant with a generator output of 100 kWp or more should be fitted with an on-site insolation measuring system. Neverthe-less, it is also worth measuring on-site insolation in plants with lower capacities.

PHO

TO: TO

M BA

ERWA

LD/LEB

HERz

PHO

TO: TO

M BA

ERWA

LD/LEB

HERz

Thermal imaging flight

Measuring insolation using a pyranometer


39

Insolation data obtained from satellite pictures may also be consulted in or-der to determine whether the PV plant is running efficiently. The yields are re-corded hourly and sent to a server via the internet once a day. There, the data are compared to the yields expected. This method achieves an average accuracy – although not very quickly – comparable to plant monitoring with PV sensors. If a fault is identified, it often cannot be recti-fied immediately because the target val-ue and actual value of the yield are only compared once a day.

Another method of monitoring a plant is the continuous comparison of output supplied by the individual module strings (string monitoring). If all the strings have been installed with the same orienta-tion, then their output should always be the same. If it is possible that partial shading could occur, this is known in ad-vance. Therefore, if a string unexpectedly falls behind the others this means that there must be a fault. String monitoring is a quick, simple and effective method of identifying yield losses.

If operational data are saved on the in-ternet, a service provider (or “technical plant manager” in the case of large-scale installations) can assume the task of monitoring the plant and then inform the operators of any faults which occur, or even take independent measures to rectify them.

Causes of faults resulting in yield reduc-tion

Yield losses can generally be attributed to three causes of faults. Component faults, installation faults and faults caused by external influences.

Component faults are more frequently found in inverters than modules. These can be due to production faults, aging or thermal overload of the inverters. Such faults often lead to the complete failure of either the PV plant or the part of the generator connected to the defective in-verters. An increasing number of inverter manufacturers are, therefore, now pro-viding long-term guarantees and service contracts. PV modules are not as badly affected by thermal overload as invert-ers, but rather by external influences, al-though this happens over relatively long periods of time. As shown by several ex-periments running for extended periods of time during the 1980s, crystalline solar modules are able to supply power for 20 years without showing significant signs of aging. Provided that the manufacturer has put a sound quality management system in place, production faults are often identified in the factory, meaning that broken cells or incomplete lamina-tion only rarely appear in a PV plant as component faults.

Installation faults rarely result in com-plete plant failure but only in partial yield reduction. Sometimes, installation faults only start to take effect after a certain time, which means that they are recog-nized far too late. If, for example, modules are installed so close to one another that there is no longer an expansion gap, the

glazing may crack due to the effects of temperature and wind. Individual mod-ules or even whole strings will continue to fail as a result of electrical connections not being installed carefully enough. In-sulation can also be adversely affected by installation faults. For this reason, it is wise to use an automatic insulation monitor, which is integrated into some inverters.

External influences primarily affect PV modules. Over the decades, UV radiation from the sun will lead to light aging. The darkening of the plastic film (browning) can lead to a reduction in module output (degradation). Weather-induced aging is only observed relatively rarely in the plastics, in which the solar cells are em-bedded. Cell damage occurs more often, which is caused by shading and subse-quent excessive heating (hot spot). By-pass or string diodes may be damaged by thermal overload or overvoltages. Invert-ers are not normally directly exposed to meteorological conditions although they are adversely affected by circuit feedback, for example.

PHO

TO: TO

M BA

ERWA

LD/LEB

HERz

PHO

TO: TO

M BA

ERWA

LD/LEB

HERz

Measuring the output of an inverter

Plant monitoring


40

Stand-Alone Power Systems and Grid-Parallel OperationThanks to their simple, modular structure, PV installations are suitable for virtually all service environments the world over. In countries lacking local power grids, they form autonomous, stand-alone power systems that can be expanded as needed, and are thus a driving force in “rural electrification”. PV plants installed in areas where power grids exist but are unreliable are something of a specialty. They operate in parallel to the grid and then bridge periods when the power fails.

As seen here on Haiti, stand-alone solutions comprising a small solar module, a charge controller and a battery have been designed for consumers who are not connected to a central power grid.

PHO

TO: SO

LARW

ORLD

AG

Stand-Alone Power Systems and Grid-Parallel Operation

41

Solar power for remote locations

Stand-alone systems are the original pre-serve of photovoltaics. The simplest in-stallations consist of a PV module and a device that consumes DC, such as a water pump. Photovoltaic systems are straight-forward to install and benefit from low operating costs. In remote regions, lo-cated at great distances from the power grid, they are therefore often unrivalled on price – particularly when the only al-ternatives are diesel generators that con-sume expensive fuel. Continually falling module prices together with rising prices for fossil fuels are also clearing a path for such systems in other markets.

If small, stand-alone installations require a 24-hour power supply, the PV plant is combined with a battery system, as is the case in weather stations, navigational aids and transmitter masts. Here, elec-tronic charge controllers are employed to ensure that the power supplied by (mostly individual) PV modules is stored in the batteries as efficiently as possible. DC power consuming equipment (such as lamps and refrigerators) is connected to the charge controller and is thus sup-plied either by the solar power generated at a given moment or by power stored in the batteries. This principle is that of the “solar home system”.

Backup systems (e.g. diesel or vegetable oil generators) improve supply security. This has led to the creation of hybrid sys-tems that can be used, for example, in hunting cabins and refuges, and even on large yachts.

With the development of PV technology, stand-alone systems have grown into au-tonomous grids and have become more diverse. If intended to supply power to schools, hospitals, entire villages or even small islands, the PV systems are usu-ally supplemented by small wind turbine generator systems as well as batteries and diesel or vegetable oil generators. Biogas plants can also be integrated into these autonomous grids.

As such grids increase in size, cheap de-vices that consume AC (refrigerators, TVs and other household appliances) are used in addition to those that consume DC, meaning that inverters become nec-essary alongside charge controllers.

It is not only possible to structure hybrid systems as either pure DC systems or mixed AC/DC systems, pure AC configu-rations are also available that are flexible and can be expanded. Special inverters are needed for such systems. A stand-alone inverter primarily has two tasks: It charges the batteries to store any solar power not used immediately and creates a stable AC network.

Additional PV systems and the fuel driv-en generators feed into the AC network, coupled with a wind turbine generator system (preferably also with a special inverter) or biogas plant when large amounts of power are needed. The better the levels of insolation and wind comple-ment one another over the course of a day, week or year, the less frequently the back-up generator is used.

Power storage systems are needed to stabilize the grid. In addition to ensuring that electricity is available around the clock as far as possible, they also decrease short-term power fluctuations which arise as a result of clouds passing over-head, for example, and cause PV output to fall by up to 80%.

If a hybrid system supplies an entire vil-lage, a micro grid is created. Several of these stand-alone systems can then be combined to form a mini grid. Stand-alone systems gradually grow together into ever larger grid units, thus represent-ing a major contribution to rural electrifi-cation in developing countries.

Using solar energy to support the power grid: Since the grid power supply is unreliable, a PV installation in Chennai (India) is used to produce power during the day. At night, a diesel generator ensures electricity is still available. Surplus solar power is stored in a battery.

3.1.

2.

7.6.

4.

9.

5.

Hybrid system

10.8.

150 kWp

Future extensions possible


42

Bridging bottlenecks

Between PV plants that supply stand-alone systems and those that feed into the public grid come installations that generate power in parallel to the grid (grid-compatible parallel operation).

Grid-parallel operation is necessary any-where where a public grid exists but the power supply is unreliable. Moreover, such systems are also practical in situ-ations where a large power consumer (such as a factory) is connected to a weak grid spur and the power demand regularly exceeds the capacity of the grid connection. In both cases, photovoltaics assists in stabilizing the power grid and bridging bottlenecks in supply.

To date, this task has been performed by diesel generators. But in view of rising oil prices and PV generation costs that con-tinue to fall, it makes far more practical sense to install PV systems. This is espe-cially true in regions with high levels of insolation. In many cases, photovoltaics is already capable of generating power for profit in these regions, as illustrated by this simple case study:

A factory in India that operates around the clock, but is plagued by frequent power failures, relies on a diesel genera-tor to supply power during the power cuts. This generator can produce power at all times of the day for 20 euro cents/kWh. Thanks to the high levels of insola-tion there, a PV installation is able to gen-erate electricity throughout the day for 10 euro cents/kWh. Both systems operate in parallel to the grid. During the day, the PV installation has priority, while at night the diesel generator is responsible for securing the power supply. Surplus solar power produced during the day can also be stored using a battery system, increas-ing the availability of that power even further. This increases the availability of the battery and makes it possible to use solar power at nighttime.

A progression of this system is based on a situation where the PV installation produces distinctly more power than the factory requires and consists of two PV generators. The larger of these supplies the factory with electricity throughout the day and feeds any surplus power into the battery system. The smaller PV generator is tasked solely with ensuring that the battery is fully charged, so that

enough power is available during the night. Wind energy installations can also be connected to this system and supply power to the factory. The diesel genera-tor is currently still needed as a backup power source, but provided the latest radical developments in battery technol-ogy continue, it will foreseeably become redundant in the medium term.

Stand-alone PV systems

DC loads

Pumpscathodic protection

AC loads

AC loads

DC loads

DC loads

DC loads

DC loads

Charge controller,battery monitoring

Lead-acid or NiCd battery,capacitor

Additional power source (diesel, wind)

PV module(s) Inverter DC-DC converter

Simple DC motors, fountain pumps, fans

Pumps with power conditioning, cathodic protection

Larger AC pumps, or other AC drives

Miniature appliances, pocket calculators,watches

Mobile applications, telecom, medical refrigeration, bus shelter lights, small SHSs

Autonomous DC loads, emergency telephones,clocks (with load management)

Remote homes, schools, hospitals - with additional power source (diesel / wind) in larger installations

<0.1

W 1 W

10 W

100

W1,

000

W>1

0,00

0 W

ApplicationPower rangeSystem


43

Protection against lightning and OvervoltageHighly excessive voltages and currents can threaten the operation of a PV plant. Such surges are mainly caused by lightning strikes, but also by faults in the grid. Ensuring a path to earth for any lightning or currents caused by overvoltage is an extremely important factor in PV plant protection.

PHO

TO: TO

M BA

ERWA

LD

Electric and magnetic fields that could damage PV plants are created by the high voltages and currents caused by lightning strikes.

Protection against Lightning and Overvoltage

44

Assessing the risks is essential

In principal, a PV plant does not generally increase the risk of a building being struck by lightning and a separate lightning protection system does not necessarily need to be constructed simply because a PV plant has been installed. Nevertheless, the VdS (German Testing Institute for Fire Protection and Security) recommends installing a lightning and overvoltage protection system for all plants with a ca-pacity of 10 kW or more. Many insurance companies follow this recommendation and only offer insurance cover if sufficient protection of this kind is in place. In indi-vidual cases, the risks should therefore be assessed in order to enable a decision in favor of or against the construction of a lightning and overvoltage protection sys-tem, and to allow plant operators to pre-sent arguments to insurance companies. If the building on which the PV plant is constructed is already equipped with a lightning protection system (e. g. a pub-lic building or venues open to the public), the PV plant must be integrated into the protection concept.

The standard DIN EN 62305 (VDE 0185-

305):2006-10 provides a comprehensive approach to internal and external light-ning protection for buildings and sys-tems. In particular, the supplementary sheets to this European standard offer practical support when deciding wheth-er or not to install a lightning protection system, as well as details on how to in-stall such systems properly. Photovoltaic installations are primarily discussed in Supplement 5 “Lightning and surge pro-tection for PV power supply systems”.

External lightning protection includes all measures for arresting lightning and conducting it to ground, and consists of a lightning current arrester, a down lead capable of carrying lightning and a grounding system which distributes the lightning current in the earth.

Priority must be given to preventing the lightning from directly hitting the modules. This is first and foremost nec-essary when the PV generator has been installed in an exposed area (elevated on a flat roof, for example). Rods or wires are used as lightning current arresters, and the core shadow of these should not be cast on the modules as far as this is possible. Somewhat smaller air terminal rods are, therefore, placed in front of the solar modules and somewhat larger ones are placed behind the modules. The exact number and spacing of the air terminal rods is given by the class of protection desired and is calculated using methods such as the “rolling sphere method”.

Indirect effects

The probability of indirect lightning ef-fects occurring is significantly higher than that of a direct lightning strike. This is because every lightning strike within a one-kilometer radius can generate cur-rent flow in the modules, module cables and in the main DC cable by means of in-duction. Conductive and capacitive cou-pling are also possible and can equally cause overvoltage.

An integrated lightning protection sys-tem comprising measures and equip-ment within the PV plant and in the building is, therefore, required. Its funda-mental purpose is to prevent inductive coupling and provide a path to earth for currents caused by overvoltage. In order to keep coupling in the module cables to a minimum, the area of the open conductor loops in the generator circuit must be as small as possible. The outgoing and return lines of the strings are, therefore, laid as close as possible to each other. The use of shielded single lines also reduces the risk of lightning ef-fects.

Surge protection devices (SPD) not only prevent inductive coupling but also the occurrence of grid-side overvoltage, and are normally built into the generator junction box. Because varistors used as voltage dependent resistors can age due to leakage currents, the combina-tion of two varistors and a spark dis-charger in Y connection is considered the safest longterm protection against overvoltage.

Surge protection measure

Surge protection measure: DC cables of the same string bundled together to avoid loops in which volt-

age surges can be induced.

PHO

TO: O

BO

BETTERM

AN

N G

MB

H 6

CO

. KG

Lightning protection system on a roof-mounted PV plant


45

Reverse current and electric arcsIncreased currents can also occur if there is a voltage drop in a string, caused for example by shading or a short circuit. If this happens, the parallel-connected strings will function like an external power source which drives a fault current in the direction of consumption (reverse current) through the modules of the de-fective string. If the reverse current resist-ance of the modules is exceeded they will start to heat up, so string diodes are used to prevent such reverse currents. Many PV plants today are, however, built with-out string diodes, as most modules now have higher reverse current resistance and will easily withstand reverse current of 10 to 20 amps.

Since DC and DC voltage are generated in a PV plant, there is a danger that non-self-extinguishing arcs could be created, which could cause fire. This danger is not present in an AC circuit because the reg-ular zero crossing of the AC’s sine curve immediately extinguishes any electric arc created. The electrical connections in the DC circuit of a PV plant must there-fore be extremely secure, because a loose connection can lead to sparking and, consequently, trigger an electric arc. As a result, when laying the DC cables of a PV plant it is standard to protect them from short circuit and ground leakages. This is achieved by tidy cable routing (e.g. not running unprotected over sharp edg-es) and the use of separate positive and negative cables, as well as double cable insulation. The DC cables used should be tested to “PV1-F” standards and marked accordingly.

String fuses in the GJB can also generally prevent the cables from becoming over-loaded in the event of faults. These are in-tended to reduce the risk of electric arcs.

PHO

TO: TO

M BA

ERWA

LD

Both direct and nearby lightning strikes pose a risk to PV plants.

PHO

TO: D

EHN

+SöH

NE G

MB

H + C

O.KG

PHO

TO: M

ICH

AEL STREIB

- SAC

HV

ERSTäN

DIG

ERPHO

TOS: W

EIDM

üLLER G

MB

H &

CO

. KG

Installation of a lightning protection system

The exposed location and expansive surface area of photovoltaic plants put them at particular risk of being affected by lightning.

Overvoltage protection modules (red and blue) in generator junction boxes


46

Cables and ConnectorsThe electrical connections in a system may be inconspicuous, but their effects should not be underestimated. As a relatively large number of electrical connections are required in order to connect the modules of a PV plant to the inverter, the losses at contact points can add up. long-lasting, secure cable connections with low contact resistances are necessary to avoid defects, losses and accidents.

Assembly of a junction box to a flexible solar module

PHO

TO: TO

M BA

ERWA

LD/G

LOBA

LSOLA

R

Cables and Connectors

47

Safe and weatherproof connections

A PV plant’s electrics consist of the DC cables between modules, generator junc-tion box and inverter, and the AC cable running from inverter to grid. The cables and wires must be laid in such a way to ensure that they are ground-fault and short-circuit proof. To achieve this, the DC installation is made up of two single-core, double-insulated cables that should be tested in accordance with the PV1-F standard. As the cables are almost exclu-sively laid outside, the insulation must be weatherproof. A three-core AC cable is used for connection to the grid if a single-phase inverter is used, and a five-core ca-ble is used for three-phase feed-in.

Cables connect individual modules to the PV generator. The module cables are con-nected into a string which leads into the generator junction box and a main DC cable connects the GJB to the inverter. In order to eliminate the risk of ground faults and short circuits, the positive and negative cables, each with double insula-tion, need to be laid separately. The sharp edges must be fitted with edge protec-tors. The minimum bend radius must be taken into account when laying the ca-bles and wires, and it is important that they are fixed in a durable and sufficient manner.

To avoid them acting like a burning fuse, which could cause fire to spread to neigh-boring houses, solar cables must not pass over or through firewalls unprotected. If laying the cables in this way cannot be avoided, they must be protected with a fire-resistant sheath. Further options in-clude laying them in fire-resistant ducts or using a fireproof bulkhead.

Solar cables, which are UV and weather resistant and can be used within a large temperature range, are laid outside. Sin-gle-core cables with a maximum permis-sible DC voltage of 1.8 kV and a tempera-ture range from –40 °C to +90 °C are the norm here. A metal mesh encasing the cables improves shielding and overvolt-age protection, and their insulation must not only be able to withstand thermal but also mechanical loads. As a consequence, plastics which have been cross-linked using an electron beam are increasingly used today. The cross-section of the ca-bles should be proportioned such that losses incurred in nominal operation do not exceed 1%. String cables usually have a cross-section of 4 to 6 mm2.

Owing to the sharp increase in copper prices, aluminum has recently gained significance as an electrical conductor. It is possible to save around 50% by using aluminum cables, particularly for under-ground cables at low and medium volt-age levels. However, their poor conduc-tivity means that they are thicker than copper cables. Careful attention must also be paid to the default breakaway torque of their screw connections, as, in comparison to copper, aluminum tends to creep under roofs which are (too) heavy. If the screw connections are too tight, the cable loosens over time, pos-sibly resulting in an electric arc, not to mention the associated risk of fire and all the consequential damage.

Inverter cable connection

PHO

TO: PH

OEN

Ix C

ON

TAC

T DEU

TSCH

LAN

D G

MB

H

Cabling work at a ground-mounted PV plant

PHO

TO: TO

M BA

ERWA

LD/PA

RAB

EL AG


48

losses add up

Connection technology has needed to develop rapidly over the last few years, as inadequate contacting can cause elec-tric arcs. Secure connections are required that will conduct current fault-free for as long as 20 years. The contacts must also show permanently low contact resistance. Since many plug connectors are required in order to cable a PV plant, every single connection should cause as little loss as possible, so that losses do not accumu-late. Given the precious nature of the solar power acquired from the PV plant, as little energy as possible should be lost.

Screw terminals and spring clamp con-nectors (e.g. in the module junction boxes and for connection to the inverter) are gradually being replaced by special, shock-proof plug connectors, which sim-plify connection between modules and with the string cables.

Crimp connection (crimping) has proven itself to be a safe alternative for attach-ing connectors and bushes to the cables. It is used both in the work carried out by fitters on the roof and in the production of preassembled cables in the factory. Here, litz wire is pressure bonded with a contact using a crimping tool, which causes both to undergo plastic deforma-tion creating a durable connection.

An alternative plug connector design has been developed to allow the connection to be fixed in place without the need for special tools: In this instance, the stripped conductor is fed through the cable gland in the spring-loaded connector. Subse-quently, the spring leg is pushed down by

thumb until it locks into place. The locked cable gland thus secures the connection permanently.

Plug connectors and sockets with welded cables are also available on the market. Such connections cannot, however, be used during installation work on the roof, but only during production in the factory.

Another development are preassembled circular connection systems for the AC range. These are intended to reduce the high levels of installation work required when several inverters are used within one plant.

Standards for plug connectors

Since PV modules generally come equipped with pre-assembled plug con-nectors, several modules can easily be connected to form a string. Connecting these strings to the inverter or genera-tor junction box, on the other hand, is not always straightforward. A variety of dif-ferent cable connectors are available on the market, and as yet no standards have been established for these interconnec-tion systems.

Plug connectors from different manu-facturers are usually either completely incompatible or they fail to provide a connection that will remain permanently snug. If the connector fits too tightly, this can cause the insulating plastic parts to break. A loose fit, on the other hand, poses the risk of creating high contact resistance. This leads to yield losses and the areas around the connection heating up, even causing an electric arc and the connector to melt.

When connecting a plug with a socket from a different manufacturer, a crosso-ver connection is created, which can generally only be proved to be reliable if complex, expensive tests are performed. In addition to measuring the contact resistance and determining the connec-tion strength, accelerating aging tests and weather exposure tests must also be carried out. Such tests will make it clear whether or not the different materials are compatible. This concerns both the metals used to manufacture the contacts and the plastic materials employed.

There are currently no crossover con-nections which have been tested in ac-cordance with DIN EN 50521 VDE 0126-3:2009-10: “Connectors for photovoltaic systems; safety requirements and tests” and approved by both manufacturers (socket manufacturer A combined with plug manufacturer B or socket manu-facturer B combined with plug manufac-turer A).

A standard for photovoltaic plug connec-tors, which should be as international and uniform as possible and is similar to that for domestic Schuko plugs, is de-sirable and necessary to ensure reliable connections between products from dif-ferent manufacturers. If such a standard were to be introduced, manufacturers would be in a position to offer reciprocal warranties for specific crossover connec-tions.

Example of strings connected in parallel

PHO

TO: M

ULTI-C

ON

TAC

T AG


49

Market Situation and ForecastsSince 2006, solar installations have grown year-on-year. This trend will continue to happen in 2013 and every year after that until at least 2017. Encouraging as that may seem, however, the picture is much more sobering when one looks at industry revenues. Whereas PV installation will grow at a double-digit rate in 2013, revenues will fall to 75 billion US dollars.

PHO

TO: TO

M BA

ERWA

LD/PA

RAB

EL AG

Jännersdorf solar park in Brandenburg (Prignitz, Germany) with an output of 40.5 MW. 168,000 polycrystalline modules generate around 38 million kilowatt hours of power per year on a site covering around 90 ha.

Market Situation and Forecasts

50

Industry revenues

Industry revenues – measured as system prices multiplied by total gigawatts in-stalled – peaked at 94 billion US dollars in 2011, but fell sharply to 77 billion US dollars in 2012. Revenue is projected to decline once again in 2013 to 75 billion US dollars, on the back of lower volume growth and continued system price de-clines, given that PV component prices continue downward.

The conflicting trend of growing volumes but falling revenues will, of course, chal-lenge solar companies to continue to re-duce their cost structures.

Globalization of the industry

But an equally imposing problem for companies will be the rapid globaliza-tion of the industry. Back in 2010, Europe accounted for more than 80% of solar demand, which then contracted to 53% in 2012. This will shrink further in 2013 to 39%, and Asia will then replace Europe as the world’s largest solar market. Histori-cally, solar companies could focus on Ger-many and a few other European coun-tries to support their business, but these same companies need to now quickly accelerate their entrance into emerging markets around the world.

Germany is predicted to be displaced by China in 2013 as the world’s largest solar market – a position that Germany has held for the last seven years, with the sole exception occurring in 2008. The United States is also forecast in 2013 to add more solar installations than Germany, which will drop down to third place, followed by Japan and Italy in fourth and fifth, re-spectively. This geographic shift presents a challenge in itself given that China is almost inaccessible to Western suppliers, with Japan proving equally challenging for non-domestic vendors, and the USA impacted by the recent anti-dumping trade case.

Midsized markets

Perhaps more important than next year’s changing rankings of the biggest mar-kets is the geographic fragmentation that we predict will accelerate in 2013. While nearly three quarters of total solar demand in 2012 came from the top 5 end markets, the total proportion will drop to 65% in 2013 as the market fragments. This is because of the increasing impor-tance of “midsized” markets installing a few hundred megawatts per year.

The good news is that more stability will result for this boom-bust industry, be-cause a single government’s incentive policy will have less impact on the overall global market. But along with this stabil-ity will come intense challenges for solar companies as they are forced to globalize business by setting up new sales and ser-vice networks, complying with local re-quirements and grid codes, and navigat-ing past the “quick-hit” markets that are here one year and gone the next.

Despite the likelihood that 2013 will be another challenging year for solar com-panies, the longer-term picture looks somewhat more positive with installa-tions – and more importantly, with indus-try revenues that are predicted to grow at a double-digit rate between 2014 and 2016. As a result, industry revenues will soar past the 2011 peak to 115 billion US dollars by 2016.

Global demand forecast

PV installation per region (GW)

60,000

50,000

40,000

30,000

30,000

10,000

2010 2011 2012 2013 2014 2015 2016

Americas Asia EMEA*

* Europe, Middle East, Africa

SOU

RCE: IH

S PV M

ARK

ET TRAC

KER Q

4 2012


51

PV module prices to stabilize in 2013 asoversupply eases

A drastic decline in prices along the silicon supply chain has taken place since March 2011. As of November 2012, Chinese mod-ule prices have declined by more than 25% on average from their 2011 levels. The drop can be seen in the figure below, which shows Chinese c-Si module prices, differentiated according to the region in which the modules were sold. The time frame spans the period from February to December 2012; figures from November to December are forecasts and estimates from IHS Solar research.

looking ahead: more stable prices predicted

Despite such gloomy developments dur-ing the course of 2012, more stable cell prices are predicted ahead. This means that c-Si module price reductions will also slow, even though the end market might still be expecting bigger price cuts. All told, IHS predicts c-Si module prices will stabilize by the middle of next year. The anticipated stabilization of prices – from polysilicon to c-Si modules – will be due to a moderate cut in production among Tier-1 polysilicon suppliers.

Energy storage systems (ESS) for PV

The FiT for small PV systems has fallen below the retail price of electricity in the world’s largest PV market, Germany. New system owners in Germany will sell their electricity for less than they are buying it back for. A residential system owner now effectively has a financial incentive to use as much of their electricity as pos-

sible. Still, the investment into a storage system is not very attractive financially. That’s why the German government has announced a subsidy program for energy storage. The subsidy program got everyone’s attention; however, its scope is much more limited than that of the original EEG. It consists in subsi-dized (reduced interest) loans and a 30% cash grant for the purchase of the stor-age system. The program is limited to PV systems up to 30 kWp. The applying PV systems are restricted in feeding to the grid at a maximum 60% of the nominal output power of the PV systems. These measures shall help to integrate more PV systems into the existing grid by cap-ping the power peaks at local level. The date of the introduction is yet to decide (as of March 2013), cf. www.kfw.de.

A strong influx of new products from in-verter manufacturers is expected to tackle this market with an array of solutions. The solutions range from inverters with the capability to have batteries attached to full solutions with batteries integrated and intelligent energy management sys-tems that switch between energy sources and charge/discharge batteries in order to achieve the most economical and effi-cient supply of electricity. IHS will provide a detailed forecast by May 2013, expecting a strong increase of PV energy storage sys-tems in 2013 and the years to come.

This article is an excerpt of IHS Solar Whitepaper on 2013 Market Predictions, December 2012. The document can be downloaded at www.imsresearch.com/media_contact.php?sector=6.

Top 5 solar markets in 2012 and 2013

GERMAnY 8,000

2012 MW InSTAllED 2013 MW InSTAllED

1

2

3

4

5

1

2

3

4

5

CHInA 5,100

USA 3,600

ITAlY 3,500

JAPAn 2,200

CHInA 6,300

USA 5,100

GERMAnY 5,000

JAPAn 3,500

ITAlY 2,900

Chinese c-Si module price by region

0.9

0.8

0.7

0.6

0.9

0.8

0.7

0.6

US$ US$FEB

2012

MA

R 20

12

APR

201

2

MAY

201

2

JUn

201

2

JUl

2012

AU

G 2

012

SEP

2012

OCT

201

2

nO

V 2

012

DEC

201

2 (Exp

)

JAn

/ F

EB 2

013 (Exp

)

EUnAFTA*ROWJAPAnCHInA

SOU

RCE: IH

S PV M

ARK

ET TRAC

KER Q

4 2012

* North American Free Trade Agreement

SOU

RCE: IH

S SOLA

R RESEARC

H, D

ECEM

BER 20

12


52

53

The Companies

54

Overview

Companies and brands presented at a glance (in order of appearance)

Overview

page 60 page 61

page 62 page 63 page 64


page 68

page 58

page 70


page 69

55

Overview

page 75 page 77page 76

Nidec ASI S.p.A.


page 81 page 83page 82

page 84

page 87

page 86page 85

page 91page 90

56

Business Areas

Business Areas

Companies (in alphabetical order)

PV m

odul

es

CPV

mod

ules

Mod

ule

junc

tion

boxe

s

Inve

rter

s

Hou

sing

Pow

er p

lant

cont

rol

Mod

ule

leve

l pow

er

man

agem

ent (

MLP

M)

Mon

itorin

g/su

perv

isio

n

Ligh

tnin

g an

d ov

ervo

ltage

pro

tect

ion

(LO

P)

Conn

ectio

n te

chno

logy

(c

able

s, pl

ugs,

switc

hes,

junc

tion/

com

bine

r/di

strib

utio

n bo

xes)

Plan

ning

and

grid

inte

grat

ion

Soft

war

e/IT

Stor

age

tech

nolo

gies

Char

ge re

gula

tors

Com

mun

catio

n se

rvic

es

Page

Company Cent

ral i

nver

ters

Strin

g in

vert

ers

Mul

ti st

ring

inve

rter

s

Isla

nd in

vert

ers

Mod

ule/

mic

ro in

vert

ers

Inve

rter

com

pone

nts

Mod

ule/

mic

ro in

vert

ers

Pow

er o

ptim

izer

s

58 ABB ö ö

60 Advanced Energy ö ö ö ö ö ö ö ö

61 AEG Power Solutions ö ö ö ö ö ö ö

62 Bonfiglioli Riduttori S.p.A. ö ö ö ö ö ö ö

63 Bosch Power Tec GmbH ö ö ö ö ö ö ö

64 Danfoss Solar Inverters ö ö ö ö

65 Diehl Controls – PLATINUM® GmbH ö ö ö ö

66 Fronius Deutschland GmbH ö ö ö ö ö

67 GoodWe ö ö ö ö

68 W. L. Gore & Associates GmbH ö ö ö ö ö ö ö ö ö ö ö ö ö

69 Ingeteam Power Technology S.A. ö ö ö ö ö ö ö ö

70 KOSTAL Industrie Elektrik GmbH ö ö

71 KOSTAL Solar Electric GmbH ö ö ö ö ö

72 LTi REEnergy ö ö ö ö ö ö ö ö

73 Mastervolt International BV ö ö ö ö ö ö ö ö

74 meteocontrol ö

75 Multi-Contact AG ö ö

76 Nidec ASI S.p.A. ö ö ö ö ö ö ö ö ö ö ö ö

77 OBO BETTERMANN GmbH & Co. KG ö ö ö

78 Phoenix Contact GmbH & Co. KG ö ö ö ö ö ö ö

65 PLATINUM® GmbH – Diehl Controls ö ö ö ö

79 Power-One ö ö ö ö ö ö ö ö ö

80 REFUsol GmbH ö ö ö ö

81 Saft ö

82 Schneider Electric ö ö ö ö ö ö ö ö ö

83 skytron® energy GmbH ö ö ö ö

84 SMA Solar Technology AG ö ö ö ö ö ö ö ö ö ö ö ö ö ö

85 Solare Datensysteme GmbH ö ö ö ö

86 SolarMax ö ö ö ö

90 Solarpraxis AG ö

87 Steca Elektronik GmbH ö ö ö ö ö ö ö ö ö

91 Sunbeam GmbH ö

57

Business Areas

PV m

odul

es

CPV

mod

ules

Mod

ule

junc

tion

boxe

s

Inve

rter

s

Hou

sing

Pow

er p

lant

cont

rol

Mod

ule

leve

l pow

er

man

agem

ent (

MLP

M)

Mon

itorin

g/su

perv

isio

n

Ligh

tnin

g an

d ov

ervo

ltage

pro

tect

ion

(LO

P)

Conn

ectio

n te

chno

logy

(c

able

s, pl

ugs,

switc

hes,

junc

tion/

com

bine

r/di

strib

utio

n bo

xes)

Plan

ning

and

grid

inte

grat

ion

Soft

war

e/IT

Stor

age

tech

nolo

gies

Char

ge re

gula

tors

Com

mun

catio

n se

rvic

es

Page

Company Cent

ral i

nver

ters

Strin

g in

vert

ers

Mul

ti st

ring

inve

rter

s

Isla

nd in

vert

ers

Mod

ule/

mic

ro in

vert

ers

Inve

rter

com

pone

nts

Mod

ule/

mic

ro in

vert

ers

Pow

er o

ptim

izer

s

58 ABB ö ö

60 Advanced Energy ö ö ö ö ö ö ö ö

61 AEG Power Solutions ö ö ö ö ö ö ö

62 Bonfiglioli Riduttori S.p.A. ö ö ö ö ö ö ö

63 Bosch Power Tec GmbH ö ö ö ö ö ö ö

64 Danfoss Solar Inverters ö ö ö ö

65 Diehl Controls – PLATINUM® GmbH ö ö ö ö

66 Fronius Deutschland GmbH ö ö ö ö ö

67 GoodWe ö ö ö ö

68 W. L. Gore & Associates GmbH ö ö ö ö ö ö ö ö ö ö ö ö ö

69 Ingeteam Power Technology S.A. ö ö ö ö ö ö ö ö

70 KOSTAL Industrie Elektrik GmbH ö ö

71 KOSTAL Solar Electric GmbH ö ö ö ö ö

72 LTi REEnergy ö ö ö ö ö ö ö ö

73 Mastervolt International BV ö ö ö ö ö ö ö ö

74 meteocontrol ö

75 Multi-Contact AG ö ö

76 Nidec ASI S.p.A. ö ö ö ö ö ö ö ö ö ö ö ö

77 OBO BETTERMANN GmbH & Co. KG ö ö ö

78 Phoenix Contact GmbH & Co. KG ö ö ö ö ö ö ö

65 PLATINUM® GmbH – Diehl Controls ö ö ö ö

79 Power-One ö ö ö ö ö ö ö ö ö

80 REFUsol GmbH ö ö ö ö

81 Saft ö

82 Schneider Electric ö ö ö ö ö ö ö ö ö

83 skytron® energy GmbH ö ö ö ö

84 SMA Solar Technology AG ö ö ö ö ö ö ö ö ö ö ö ö ö ö

85 Solare Datensysteme GmbH ö ö ö ö

86 SolarMax ö ö ö ö

90 Solarpraxis AG ö

87 Steca Elektronik GmbH ö ö ö ö ö ö ö ö ö

91 Sunbeam GmbH ö

58

ABB has been working for decades to offer products and solutions to reduce the environmental impact of energy sys-tems. ABB manufactures and supplies a broad range of leading-edge solutions for the photovoltaics (PV) market, suit-able for the smallest building applica-tions, right up to large megawatt-sized power plants. The comprehensive port-folio includes single components such as solar inverters, low voltage products, transformers, and switchgears up to com-plete turnkey power plants. Whether the PV systems are large power plants or industrial, commercial or residential building applications, ABB’s high-quality products, systems and services provide optimum return on investment.

Powerful solar inverters with global presenceThe ABB solar inverter utilizes over 40 years of advances in inverter and power converter technology that has contributed to ABB becoming the world leader in frequency converters and one of the biggest suppliers of wind turbine converters. ABB offers a complete portfo-lio of solar inverters from small transfor-merless single-phase string inverters up to transformerless central inverters with power ranges amounting to hundreds of

kilowatts. Furthermore, ABB solar invert-ers are supported through a worldwide sales and service network that provides a complete range of life-cycle services.

ABB central inverters for photovoltaic power plantsABB central inverters are aimed at PV pow-er plants and large industrial and com-mercial buildings. Based on ABB’s market-leading technology platform in frequency converters, the central inverters comprise proven components with a long track record of performance excellence in de-manding applications and harsh environ-ments. Equipped with extensive electrical and mechanical protection, the inverters are engineered to provide a long and reli-able service life of at least 20 years. A wide range of options like remote monitoring with string current measurements, field-bus connections and integrated DC cabi-nets are available. Thanks to the inverters’ certificates and advanced and flexible grid support functions, ABB central inverters can meet all applicable network connec-tion requirements. During the last ten years, ABB has deliv-ered over 100 GW of power converters on the same platform that is used for central inverters. During their first few years of use alone, ABB central inverters gained an

ABB Oy, Power ConversionAddress: Hiomotie 13 00380 Helsinki · FinlandPhone: +358 (0)10 22 11Email: [email protected] Web: www.abb.com/solar

Year founded: formed in 1988, merger of Swiss and Swedish engi-neering companies with predecessors founded in 1883 and 1891Employees: 145,000 (ABB Group)

ABBInverters for the Entire Spectrum without Losing a WattABB offers a comprehensive solar inverter portfolio. With decades of experience in power technology products, ABB has the know-how, life-cycle services and personnel to support PV installations worldwide for years to come.

50.6 MWp PV power plant in Pobeda, Bulgaria, powered by ABB PVS800 central inverters

4.99 MWp PV power plant in Malmesbury, UK, powered by ABB PVS800 central inverters

Business area: inverters

59

established position in the solar business, with nearly 1 GW of installed capacity. The inverters are available from 100 to 1,000 kW.

ABB string inverters for residential buildingsABB string inverters are designed for PV systems installed on residential, commer-cial or industrial buildings. The inverter’s all-in-one design includes the necessary protection functions built into the invert-er, which reduce the need for costly and space-consuming external protection de-vices and larger enclosures. The result is a more compact, reliable, safer and cost-effective solution, especially in installa-tions using multiple inverters. The heart of the inverter is the intuitive control unit equipped with a graphical display. It offers a comprehensive range of key functionalities that are easy to use with built-in assistants and a help menu. The control unit has three different mount-ing options. It can be integrated in the in-verter housing or mounted separately on a wall to monitor inverter performance from outside the installation room. It can also be wirelessly connected to enable the inverter to be installed in a remote part of the site and monitored wirelessly from inside the main building. The invert-ers are available from 3.3 to 8 kW.

Turnkey solution for large-scale solar power generationThe ABB megawatt station design capital-izes on ABB’s long experience in the devel-opment and manufacture of secondary substations for electrical authorities and major end users worldwide in conven-tional power transmission installations. A station houses two ABB central inverters, an optimized transformer, medium-volt-age switchgear and a monitoring system, which connect a photovoltaic power plant to a medium-voltage electricity grid eas-ily and rapidly. All components within the megawatt station are part of ABB’s prod-uct portfolio. The steel-framed insulated container comes complete with a concrete foundation, also designed and produced by ABB. The station’s thermal insulation enables operation in harsh temperature and humidity environments and is de-signed for at least 20 years of operation. The megawatt station is available in two sizes: 1 MW and 1.25 MW.

ABB is a leader in power and automa-tion technologies that enable utility and industry customers to improve their per-formance while lowering environmental impact. The ABB Group of companies op-erates in around 100 countries and em-ploys about 145,000 people.

ABB PVS800 central inverter, 1,000 kW

ABB PVS800-MWS megawatt station

ABB PVS300 string inverter, with control unit

60

Customer experienceAE Solar Energy enables utility-scale and commercial solar project stakeholders to offer system owners a lower Levelized Cost of Energy (LCOE) and the confidence that their PV system will deliver on long-term production goals. With more than 30 years of leadership in delivering inno-vative energy solutions, combined with a legendary reputation for customer ser-vice and a strong balance sheet, AE is a trusted partner to solar project develop-ers, financiers, and beneficiaries around the globe.

Innovation AE is never satisfied: From our roots in re-liability and LCOE to continually improv-ing our quality, systems and people, we ensure that energy is delivered, period. We pioneer improvements in distribut-ed generation, grid interactivity perfor-mance, utility interactive functionality, and energy management solutions.

Advanced Energy Founded in 1981, Advanced Energy (Nasdaq: AEIS) is a global leader in reliable power conversion solutions. AE’s solar energy business delivers highly reliable inverters, complementary BoS products, and O&M services that allow our customers to secure more solar projects and grow their business.

Energy delivered™AE delivers highly reliable and efficient inverters designed with an architecture optimized to deliver the LCOE. Our simpli-fied BoS solutions reduce system design support, project management time and increase savings on installation. Simply put, AE delivers life-cycle performance.

Solar site solutionsAE delivers whole-site operations and maintenance service plans that increase the reliability of customers’ PV systems. AE global services is dedicated to respond-ing quickly to issues, whether that means rolling a truck, providing phone support or anything in between. We provide applica-tion engineering support and warranties for up to 20 years, partnering with cus-tomers for the entire project life-cycle.

AE Solar Energy Address: 20720 Brinson Blvd. Bend, OR. 97701 · USAPhone: +1 877 312-3832Fax: +1 541 312-3840Email: [email protected]: www.advanced-energy.com/solarenergyYear founded: 1981Employees: 1,500

150 MW solar project utilizing AE’s 2 MW integrated skid solutions

AE’s PowerStations generate electricity dependably, optimize Levelized Cost of Energy (LCOE)

and help stabilize grid operation.

Solar plant in Vermont, USA

Business areas: invertersmonitoring/supervisionLOPconnection technologyplanning and grid integrationsoftware/IT

61

Using their tried and proven technolo-gies, AEG Power Solutions is well-placed to deliver smart solutions for photovol-taic and storage systems.

The heart of any plant is the central in-verter, designed to convert DC power from the solar panels to AC power for the utility grid.

AEG Power Solutions offers differ-ent models of central inverters, named the Protect PV.250, PV.500, PV.630 and PV.800, which have an outstanding con-version efficiency.

The basic models of the Protect PV product line are designed for indoor use. More advanced models can be placed outdoors directly.

The most advanced models are included as part of the turnkey solutions in con-tainers, abbreviated TKS-C. The TKS-C is a fully integrated solution that has been developed specifically for use in photo-voltaic power plants. It comprises:• up to two solar central inverters• switchgear• a medium-voltage transformer• measuring and monitoring

components• data communication capabilities

AEG Power Solutions AEG Power Solutions offers a comprehensive portfolio of premium power supply and control products, systems, solutions and services.

In order to bridge the gap between ex-ploiting power availability at times that cannot be readily predicted and delivering sufficient power at times of demand, AEG Power Solutions has developed a BESS (Battery Energy Storage System) solution.

Through its Battery Energy Storage Sys-tem, AEG PS provides a solution that meets the needs of a rapidly changing energy market. The components that make up the BESS are housed in com-bined containerized units with control managed via the AEG PS control unit, which can be operated locally on site or remotely via the Internet.

The power electronics that are used in the BESS have been developed specifical-ly for complex, modern grid applications and offer customers the benefit of estab-lished, robust, reliable and field-tested equipment.

The total concept is flexible and adjust-able to many requirements and is appli-cable for almost all grid codes worldwide.

Business areas: inverters

storage technologiesplanning and grid integration

monitoring/supervisionpower plant control

Protect PV.500-PV.800 solar inverter

AEG Power Solutions GmbHAddress: Emil-Siepmann-Straße 32 59581 Warstein-Belecke · GermanyPhone: +49 (0)2902 763-141Fax: +49 (0)2902 763-1201Email: [email protected]: www.aegps.com

Year founded: 1946Sales volume: 428 million euros (2011, worldwide) Employees: > 1,650 (2011, worldwide)

PV park in Möhnesee, Germany

AEG Power Solutions – Competence Center in Warstein-Belecke

Battery Energy Storage System

62

Thanks to the global nature of its dis-tribution network and its wide range of reliable high-efficiency solutions, pres-tigious international EPCs and IPPs trust Bonfiglioli to supply inverters for large-scale photovoltaic installations in Europe, Asia and North America.

In 2008, Bonfiglioli supplied its solutions for the world’s largest photovoltaic field at the time (51 MW) in Spain. In 2010, Bonfiglioli supplied inverters for one of Europe’s largest PV fields (70 MW) in Italy and in 2012, a PV field with an output of 60 MW fitted with Bonfiglioli invert-ers was put into operation in Bulgaria. Bonfiglioli’s long history and consolidated international presence make it a reliable and bankable investor and have allowed the Bonfiglioli Group to contribute to the start-up of major installations in emerg-ing markets.

Bonfiglioli Riduttori S.p.A. Bonfiglioli manufactures and designs power conversion systems from 3 MW turnkey solutions down to 30 kW compact devices, for medium to large commercial and utility-scale installations.

Bonfiglioli’s RPS Stations, which are avail-able in a vast range of power ratings from 280 to 3,100 kW, provide turnkey solu-tions for complete photovoltaics field management for all large-scale ground-mounted installations. RPS Stations are produced and tested directly at the plant to ensure the highest standards of qual-ity and efficiency along with reduced costs. As a result, customers receive a fully equipped, ready-to-connect system in impressively short times.

The RPS TL modular inverters at the heart of every Bonfiglioli RPS Station guarantee highest system yields and excellent inter-national grid code compatibility thanks to the modular engineering and German technology that distinguish all Bonfiglioli inverters.

In-depth understanding of markets and market dynamics, 17 commercial subsidi-aries, four photovoltaic production cent-ers on three continents and a wide range of high-tech inverters make Bonfiglioli a long-standing and risk-free industry play-er for photovoltaic field developments anywhere in the world.

Bonfiglioli offers a worldwide and localized service network.

Bonfiglioli Riduttori S.p.A. Address: Via Giovanni XXIII, 7/A 40012 Lippo di Calderara di Reno – Bologna · ItalyPhone: +39 0516473111Fax: +39 0516473126Email: [email protected]: www.bonfiglioli.com

Year founded: 1956Employees: 3,300

Business areas: invertersconnection technology planning and grid integration monitoring/supervisionsoftware/IT communication services

Bonfiglioli RPS Station: turnkey solutions customized for your market

Bonfiglioli RPS TL

63

Bosch Power Tec GmbH is a 100% sub-sidiary of Robert Bosch GmbH and was founded in January 2011. The business purpose is the development and sale of electronic power components for use in the renewable energy industry. The port-folio includes highly-efficient solar in-verters, pre-fabricated inverter stations, system management solutions and pio-neering electricity storage technologies. Extensive service and maintenance con-tracts for every product group enhance the Bosch Power Tec range.

Solar storageThe VS 5 Hybrid comprises a transformer-less 5 kW inverter, a lithium-ion battery and a management system. The storage of solar power makes it possible to ensure one’s own needs are met with PV electric-ity even outside of daylight hours. The en-ergy is taken from the PV system and fed directly into the power grid, taken from the storage system or simultaneously made available from both sources. Grid power is only used when not enough en-ergy can be made available this way. The system also operates self-reliantly in the event of a power failure.

Bosch Power Tec GmbH Solar Power Day and NightThe Bosch Group is a leading global supplier of technology and services, active in the fields of automotive technology, energy and building technology, industrial technology and consumer goods.

With the VS 5 Hybrid system, the self-sufficiency level of a four-person house-hold can be increased to 75% and more. The VS 5 Hybrid is the only system in the world that can supply solar energy to both single- and three-phase house-holds at any time, day or night.

Made in GermanyWe have been producing and develop-ing our products exclusively in Germany for more than 30 years, and rely on high-quality materials and industrial compo-nents in our development work – help-ing us to ensure that our products will last for a long time even under harsh conditions.

Bosch Power Tec GmbHAddress: Sachsenkamp 520097 Hamburg · GermanyPhone: +49 (0)391 813 3030Fax: +49 (0)40 6450 2101Email: [email protected]: www.bosch-power-tec.de

Year founded: 2011Employees: 180

The VS 5 Hybrid regulates energy flows and reaches a household self-sufficiency level of 75% and more.

The VS 5 Hybrid is a fully-integrated

system and has already received

numerous awards.


monitoring/supervision connection technology

storage technologies

The VoltApp is the mobile iPhone and

iPad monitoring solution for solar

installers and system owners.

64

Danfoss is a global company with over 40 years of experience in power elec-tronics. Danfoss Solar Inverters develops and manufactures a comprehensive range of grid-connectable, photovoltaic invert-ers for all PV applications, and is repre-sented in more than 20 countries world-wide. The Danfoss inverter range (from 2 to 15 kW) provides the smart solutions needed to develop your PV set up.

• The TLX series 3-phase transformerless inverter range from 6 to 15 kW.

• The DLX series 1-phase transformer-based inverter range from 2 to 4.6 kW.

Solutions for all PV system rangesPlanning a PV system that reliably deliv-ers maximum yield at minimum cost is possible with a Danfoss solar inverter so-lution. Whether you are designing a resi-dential, commercial or large-scale power plant, a fully optimized system will raise the energy yield while lowering system costs.

Residential solutionsBoth the DLX and TLX series offer an in-verter and web server in one solution. Just one inverter is needed for installa-tions up to 17 kWp.

Danfoss Solar InvertersDanfoss Solar Inverters – Smart Solutions We supply reliable, flexible and user-friendly inverter solutions for residential, commercial and large-scale applications worldwide.

Commercial solutionsThe TLX series with three independent maximum power point trackers (MPPT) and a high voltage level is designed to achieve the layout flexibility needed to maximize the energy yield of the area available – especially when encountering complex roofing challenges.

Large-scale solutionsThe TLX series is also perfect for large-scale applications thanks to the ability to reduce the effects of shading, allowing for more PV per m2, and closer placing of module rows.

Reliable and proficient partnerFrom planning and installation to trou-bleshooting and service – in addition to having one of the industry’s most expe-rienced solar support teams, Danfoss offers clean and efficient solar energy solutions for all applications. For a com-prehensive overview of our products and services, please visit us at www.danfoss.com/solar.

Danfoss Solar Inverters A/SAddress: Ulsnaes 1 6300 Graasten · DenmarkPhone: +45 7488 1300Email: [email protected]: www.danfoss.com/solar

Year founded: 1933 Employees: 23,000 (worldwide)

DLX features an integrated web server, high efficiency and access to real-time data via the Danfoss SolarApp.

TLX Pro powers the 80+ MW facility in Eggebek, Germany; one of the largest PV plants in the world

The TLX Pro series offers control of up to 100 inverters from a

single self-designated inverter.

Business areas: inverters monitoring/supervision software/IT

65

PLATINUM® string inverters in the 2 to 22 kW power range offer the right so-lution for every system size and are manufactured to the highest qual-ity. Intensive quality testing ensures a particularly low failure rate, producing robust components. The ten-year ex-works warranty and the option to ex-tend it to 20 years for the majority of all products is standard for PLATINUM®.

PLATINUM® products also comprise intel-ligent devices to monitor the power out-put of photovoltaic systems.

The WebMaster Home optimizes private consumption and visualizes any number of consumers, enabling intelligent ener-gy management.

The PLATINUM® battery, which stores solar energy and makes it available 24/7, supplements high-quality solar tech-nology. With capacities ranging from 4.6 kWh to 41 kWh, it is compatible with all PLATINUM® photovoltaic systems or can be integrated into existing systems.

PLATINUM® places emphasis on custom-er service as well as product quality. The company therefore runs regular training events for dealers, sales staff and instal-lation engineers in its headquarters in Wangen im Allgäu.

PLATINUM® experts help customers to find the right solution for difficult chal-lenges – competently and quickly, either over the telephone or on-site.

PLATINUM® GmbH(formerly known as Diehl Controls)Address: Pfannerstraße 75 88239 Wangen · GermanyPhone: +49 (0)7522 73-700Fax: +49 (0)7522 73-710Email: [email protected]: www.diehl.com/photovoltaics

Employees: 90

PLATINUM® headquarters in Wangen im Allgäu

PLATINUM® inverter manufacturing plant

Diehl Controls – PLATINUM® GmbHPLATINUM®: Premium Brand for Photovoltaic Inverters PLATINUM® offers inverter technology at the highest performance level. DIVE® technology, SiC components and RAC-MPP® for rapid MPP location make PLATINUM® inverters, which boast peak efficiencies in excess of 98%, rank among the best.

Pulls out a cool 98.4% – the PLATINUM® R3 inverter.

Business areas:inverters

monitoring/supervision storage technologies

66

Fronius, with its headquarters based in Austria, has been researching new tech-nologies for converting electrical energy since 1945. That’s more than 60 years of experience, progress and continuous in-novation. Fronius’ Solar Electronics divi-sion has been involved in photovoltaics since 1992 and sells its products through a global network of sales partners.

Producing and selling qualityAs a quality leader, Fronius develops and produces high-performance inverters for grid-connected solar power systems from 1 kW upwards. The product range is complemented by an extensive range of components for professional system monitoring, data visualization and analy-sis – all available as stand-alone product add-ons.

Living sustainablyUsing renewable energy and protecting resources are important parts of the cor-porate culture at Fronius. The Fronius Ac-tive Energy Tower in Wels (Austria) with its active energy design ensures that the building operates without generating any CO2 emissions. The climate-protec-tion façade provides shade while simul-taneously generating energy that can be used in the tower.

Fronius Deutschland GmbHFronius: Innovative Products and Technical Advances The highest possible level of quality is at the forefront of all of Fronius’ activities and manifests itself in powerful, grid-connected inverters and the wide range of system monitoring products.

Fronius Galvo – specializing in private consumption

The Fronius Active Energy Tower operates without gen-

erating any CO2 emissions.

Innovative products and new technologiesIn the development of PV inverters, Fronius has thought out new technolo-gies, searched for innovative solutions, and has found completely new answers. The result: highly functional grid-con-nected inverters, which interact optimal-ly with all solar modules.

Additionally, Fronius also provides user-friendly data communications systems for individual PV system monitoring. The hardware components are quick and easy to install, the software easy to operate. Customers can access their PV system’s performance data anytime and anywhere via the internet, smartphones or tablet PCs.

Business areas: inverters monitoring/supervision software/IT

Fronius Deutschland GmbHAddress: Am Stockgraben 3 36119 Neuhof-Dorfborn · GermanyPhone: +49 (0)6655 91694-0Fax: +49 (0)6655 91694-50Email: [email protected] Web: www.fronius.de


The Fronius Agilo central inverter can be completely installed and maintained by the installer.

67

GoodWe has so far already developed and produced six series of solar invert-ers (the SS, DS, DT, DI, PB and MT series), ranging from 1.5 to 500 kW. The maxi-mum conversion efficiency reaches up to 98.8%, while MPPT efficiency is greater than 99.5% and THDi is less than 1%, rep-resenting the world-leading level.

High-performance inverterGoodWe solar inverters are designed in Germany and assembled in China. At the end of 2012, GoodWe’s GW4000-SS inverter passed the Photon Test and was awarded a “Double A” evaluation, as well as being ranked world number one in the 4 kW series and among the world’s top three in the 1.5–5 kW series. Our products have so far obtained many international certificates, such as the CGC, CEI 0-21, VDE, TÜV, CE, G83, G59 and SAA certifi-cates, and have become listed by bodies and authorities such as the CEC, Western Power and the Danish government.

New arrival: hybrid inverterThe GoodWe PB series bidirectional energy-storage inverter can control the flow of hybrid energy and can be used in both on-grid and off-grid PV systems by switching it automatically or manually

according to the system’s working situ-ation. During the day, the PV plant gen-erates electricity which can be provided to the loads, fed into the grid or used to charge the battery. The energy stored can be released when the loads require it during the night. Additionally, the power grid can also be used to charge the stor-age devices via the inverter.

Smart monitoring systemWe provide our customers with a flexible monitoring solution. Our customers can log in to our monitoring website or use smartphone apps to check power plant information.

Advantages of internet monitoring:• two basic monitoring choices:

Wired RS485 or Wi-Fi• automatic transmission of data to

our global PV station monitoring web server via the internet

• support with iOS/Android apps, rich and visual graphic display

• equipped with data collector designed to ensure data security for enterprises

GoodWe EuropeAddress: Lise-Meitner-Straße 1-13 (Haus 1) 42119 Wuppertal · GermanyPhone: +49 (0)202 94228160Fax: +49 (0)202 94228161Email: [email protected]: www.goodwe.de


GoodWe AustraliaAddress: Melbourne, VIC · AustraliaPhone: +61 432 180 156Email: [email protected] Web: www.goodwe.de

GoodWe ChinaAddress: No.189 Kunlunshan Rd., SND, Suzhou, 215163 · ChinaPhone: +86 512 6239 6771Phone: +86 512 6239 7972Email: [email protected]: www.goodwe.com.cn

GoodWe inverter family: from 1.5 kW to 500 kW

GoodWeGoodWe Solar Inverter – World-Class Supplier of PV Distributed EnergyGoodWe is a rapidly developing inverter manufacturer. With smart monitoring solutions, their high-performance solar inverters have been widely applied in residential and commercial rooftop systems as well as power plants.


monitoring/supervisionstorage technologies

“A compact, unadorned 4 kW inverter from China has passed the PHOTON test with a more than

respectable result: Its efficiency is as impressive as its operation is convenient.” Photon International

68

Reliable performance and ensuring the long life of your productGORE® Protective Vents improve the per-formance and extend the life of your so-lar components by equalizing pressure, reducing condensation and preventing contamination. Constructed of a unique membrane with billions of pores 700 times larger than an air molecule, GORE® Protective Vents allow air to flow freely in and out of the housing, which prevents stress on seals. With continuous diffusion of moisture vapor, these vents also reduce condensation that compromises com-ponents. At the same time, Gore’s vents protect sensitive electronics because the membrane pores – which are 20,000 times smaller than a drop of water – serve as a barrier against water, dirt and debris. Ensure the reliability and long-lasting per-formance of your solar components with GORE® Protective Vents.

W. L. Gore & Associates GmbHSecure Sensitive Electronics with GORE® Protective VentsWith proven expertise in the solar industry for more than ten years, Gore has set new standards for reliable, high-performance venting solutions that protect sensitive electronics in solar equipment.

Optimal solution for many applications GORE® Protective Vents are engineered with screw-in, snap-in or welded mem-brane constructions that meet solar in-dustry standards. This versatile portfolio simplifies integration into the design of your product, be it a junction box, string combiner box, micro/string inverter, CPV module or tracking equipment. Select from multiple options to choose the best GORE® Protective Vent for your product design.

The global solution As a technology-driven company focused on innovation, Gore has delivered venting solutions for millions of rugged applica-tions worldwide over the past 30 years. With sales and R&D offices throughout the world, and manufacturing sites in the USA, Japan, China and Europe, Gore deliv-ers more than a venting product – our engineers will work with you from the initial product concept through rigorous testing and integration into the manu-facturing process. Choose Gore as your partner for reliable performance.

GORE® Protective Vents improve the performance of your product under all conditions.

W. L. Gore & Associates GmbH Address: Wernher-von-Braun-Straße 18 85640 Putzbrunn · GermanyPhone: +49 (0)89 4612-2211Fax: +49 (0)89 4612-2302Email: [email protected]: www.gore.com


Business areas: CPV modulesmodule junction boxesinvertershousingMLPMmonitoring/supervisionconnection technology

Available in many sizes and forms, GORE® Protective Vents are easily

integrated into your enclosure.

GORE® Protective Vents improve reliability, allowing continuous

airflow while blocking contaminants.

69


monitoring/supervisionsoftware/IT

With manufacturing facilities in Spain, China and the USA, and subsidiaries in Germany, Italy, France, the USA, the Czech Republic, Poland, Brazil, Mexico, South Africa, China, Chile and India, Ingeteam can satisfy the needs of its clients world-wide. Furthermore, Ingeteam’s Service Division provides operation and mainte-nance services to more than 400 MW of solar PV installations worldwide.

In the field of solar energy, Ingeteam has already overcome technology, and regula-tory and integration roadblocks to offer holistic electrical equipment solutions in many solar installations operating throughout the world.

Ingeteam’s latest innovations include the new Ingecon® Sun Power Max 1 MW central inverter for large-scale PV instal-lations, which reaches an output power of 1,019 kW and a maximum efficiency of 98.8%. In order to meet households’ new energy needs, Ingeteam has also just pre-sented the Ingeteam Smart House con-cept, a global energy management solu-tion for residential and industrial use that allows for increased on-site consumption. Moreover, Ingeteam has launched the new Ingecon® Sun 1Play (2.5 to 10 kW) and Ingecon® Sun 3Play (10 to 40 kW) inverter

Ingeteam Power Technology S.A. “The formula of the new energy: i + c” At Ingeteam each project is addressed from the concept of i+c – innovation to develop the optimal solution and commitment to provide an excellent service.

families with improved features that in-clude higher efficiency levels. Finally, the Ingecon® Sun Training platform offers a wide range of on-site training courses and live webinars aimed at professionals in the PV sector.

Ingeteam is a global corporation special-ized in six different sectors (energy, in-dustry, marine, traction, basic technolo-gies and services) that are all customer oriented and based on power and control electronics, electrical machines and appli-cation engineering. Thanks to its division-based structure and sustainable growth policy, Ingeteam enjoys a privileged, competitive position and has strongly established itself as one of the leading companies in the electronics and electro-technical sector.

Ingeteam, S.A.Corporate HeadquartersAddress: Parque Tecnológico de Bizkaia, Edificio 10648170 Zamudio-Bizkaia · SpainPhone: +34 944 039 710Fax: +34 944 039 800Web: www.ingeteam.com

Ingeteam Power Technology, S.A.Energy Division HeadquartersAddress: Avda. Ciudad de la Innovación, 1331621 Sarriguren-Navarra · SpainPhone: +34 948 288 000Fax: +34 948 288 001Email: [email protected]: www.ingeteam.com

Year founded: 1972 (Ingeteam Group)Employees: 3,000 (Ingeteam Group, world-wide)

Ingeteam Smart House, a global energy management

solution for residential and industrial use

The Ingecon® Sun 1Play inverter family, able to withstand extreme temperatures

PV on-roof installation at the Lamborghini factory (Italy) powered with Ingecon® Sun inverters

70

KOSTALKOSTAL – Intelligent Photovoltaic Solutions for Every RequirementAs part of the KOSTAL group – a family-owned and internationally active company from Germany with more than 100 years of tradition – KOSTAL Industrial Electronics and its sales company for solar inverters KOSTAL Solar Electric offer comprehensive solutions in the field of photovoltaics. In this sector KOSTAL focuses on solar module connection technology and its PIKO inverters.

Business areas: module junction boxesconnection technology

KOSTAL Industrial Electronics and KOSTAL Solar Electric – simply a smart connectionThe KOSTAL “Smart connections.” philoso-phy is based on four competitive advan-tages: KOSTAL family, real partnership, quality-offensive thinking and future programs. The interaction of these fac-tors brings about smart connections be-tween KOSTAL and its partners, as well as between the products and the product benefits. These connections are designed to obtain success in the long run.

PV junction boxes – smart connections for solar modulesKOSTAL Industrial Electronics is able to draw on the extensive experience in the development and production of solar module connection technology that it has been garnering since 1998. Taking into account the different customer re-quirements, a comprehensive portfolio of customer-specific and universally usable solutions has been acquired. This wide array of products ranges from standard solutions to fully automatable options.

KOSTAL has developed innovative con-cepts for solar module connection technology, such as leadframe technol-ogy, and these have become firmly es-tablished in the market. To round off the product range KOSTAL offers PV plug con-nectors – a reliable solution for the whole PV system.

PV module connection technology from KOSTAL is always a smart connection – today, tomorrow and in the future.

KOSTAL Industrie Elektrik GmbH(KOSTAL Industrial Electronics)Address: Lange Eck 11 58099 Hagen · GermanyPhone: +49 (0)2331 8040-4800Fax: +49 (0)2331 8040-4811Email: [email protected]: www.kostal.com/industrie

Year founded: 1995

Smartconnections.

Fully automatable SAMKO 100 04 PV junction box with integrated cable holder

Hagen/Westphalia – home of KOSTAL Industrial Electronics

KSK 4 PV plug connector

71

PIKO inverters: flexible, communicative, practicalKOSTAL Solar Electric’s product range comprises PIKO-brand single-phase and three-phase inverters in various power classes. The advantages of PIKO invert-ers can be described using the following adjectives: flexible, communicative and practical. The high input voltage range and up to three independent MPP track-ers provide maximum benefits and flex-ibility in the field of application as well as simple handling.

All PIKO inverters include a comprehen-sive communication system and an inte-grated data logger which stores the data of the PV system for up to a year. Further communication options range from the provision and monitoring of all impor-tant data – with the aid of the integrated interfaces – to the control of external de-vices. The PV system can be monitored both locally and remotely using the PIKO Data Communicator for monitoring via digital picture frames, the web server,

the PIKO Master Control, and the PIKO Solar Portal.

In 2013, KOSTAL will start selling its PIKO Battery Inverter with an integrated ener-gy management system. Taking econom-ical and technical aspects into considera-tion, the system regulates whether the energy produced by the PV system will be fed into the public grid, stored temporar-ily in the battery or used for energy con-sumption.

Via local distribution companies in Spain, Italy, France and Greece, KOSTAL Solar Electric offers on-site sales, service and training in the local language.

The KOSTAL seminars provide customers and partners new perspectives by pro-viding the latest information on gained experience and new developments to en-sure they are up-to-date and to allow for the exchange of knowledge.

KOSTAL Solar Electric GmbHAddress: Hanferstraße 6 79108 Freiburg i. Br. · GermanyPhone: +49 (0)761 47744-100Fax: +49 (0)761 47744-111Email: [email protected]: www.kostal-solar-electric.com

Year founded: 2006

PIKO Battery Inverter with integrated energy management system

The KOSTAL team – a strong partner


monitoring/supervision storage technologies

communication services

PIKO Data Communicator

72

“Vision always opens up new perspectives.” – CEO Dr. Wolfgang Lust

LTi REEnergy belongs to the LTi group of companies, which has been successfully developing inverters for a wide variety of applications and producing them in large numbers for over 40 years. The group enjoys international success with over 1,000 employees worldwide, branch of-fices on three continents, as well as more than 30 sales and service points. LTi has always stood for technologically innova-tive products of the highest quality. It has performed pioneering work in the field of energy technology right from the start, and will continue to do so in the future.

The range of products includes:• central inverters from 40 to 300 kW

for photovoltaic systems (roof systems)

• central inverter stations from 200 kW to 2.4 MW for photovoltaic power plants, as well as container stations

• electronics and active power supply in mini CHP plants

• ORC systems to generate power from process and waste heat

• robust pitch systems for rotor blade adjustment in wind turbines

LTi REEnergyThe Best Possible Plant Efficiency – with PVmaster Inverters from LTi REEnergy

The photovoltaic portfolio consists of a variety of topologies and services, which enable LTi REEnergy to be pre-pared for varying regional requirements worldwide, standards and regulations, demanding environmental conditions or difficult logistical and transport situ-ations. Depending on the requirements and conditions, the “PVmaster” central inverter series can be used in grid-con-nected operations or in a variety of stand-alone applications.

To guarantee on-going product optimi-zation, LTi developers have succeeded in developing a new inverter topology with a peak efficiency of 99.2%, which is almost certainly unrivalled anywhere in the world to date. What is special about the new technology is that the increase in efficiency has not been achieved by us-ing material-intensive circuits.

On the “roof of the world” in Tibet, at an altitude of 4,000 meters, PVmaster II units

are delivering optimum yields.

Business areas: invertershousingpower plant controlmonitoring/supervisionsoftware/ITcommunication services

LTi REEnergy GmbHAddress: Heinrich-Hertz-Straße 18 59423 Unna · GermanyPhone: +49 (0)2303 779-0Fax: +49 (0)2303 779-397Email: [email protected]: www.lt-i.com

Year founded: 1971 (LTi Group)Sales volume: > 150 million euros (LTi Group) Employees: > 1,000 (LTi Group)

CEO Dr. Wolfgang Lust

PVmaster (TT, EN and EM) Container Station and PVmaster Concrete Station from LTi REEnergy

73


monitoring/supervisionconnection technology

storage technologiescharge regulators


Today, Mastervolt has branches on all continents of the world. Since January 2011, Mastervolt has been a subsidiary of Actuant, a globally active technology group. The association with a financially strong, listed corporation will allow Mas-tervolt to continue its growth course and to bring innovative products and tech-nology to the market even faster.

Flexible technology optimizedfor installers’ needsMastervolt supplies photovoltaic inverters ranging in output from 0.5 kW to 30 kW. Mastervolt’s IntelliConcept, which is used in the company’s devices, is designed to achieve 5 to 10% more yield, even in varia-ble weather conditions. This allows a vari-ety of plant sizes and different types of so-lar modules to be covered with relatively few inverter types. This flexibility reduces training times and storage requirements for installers and distributors alike. Ow-ing to their low weight and smart design, Mastervolt products are optimized for easy installation.

Business operations tailored tocollaborationMastervolt has also tailored its business operations to achieve the best possible collaboration with partners and installers.

Mastervolt International BV Maximum Yield – WorldwideFor more than 20 years, Mastervolt has been developing, manufacturing and distributing technologies for independent electricity generation. Mastervolt launched its first photovoltaic inverter, the SunMaster 130, as early as 1993, making it a true pioneer in the solar industry.

The company guarantees a unified and transparent distribution structure. All products, including inverters for large-scale solar power plants with capacities of several MW, are solely available through Mastervolt’s distribution partners.

Mastervolt International BVAddress: Snijdersbergweg 93 1105 AN Amsterdam ZO · The NetherlandsPhone: +31 (0)20 3422-100Fax: +31 (0)20 3422-169Email: [email protected]: www.mastervolt.com


IntelliWeb:online overview of your

PV system

IntelliTrackAdditional yield by tracking fast weather change.

IntelliCoolStable high efficiency and constant high power.

IntelliGridStable operation during small grid disturbances.

IntelliWebIntegrated monitoring for early warning on system fault.

IntelliPeakMaximizes efficiency where it’s needed most.

IntelliShadeMaximizes production even under shaded conditions.

AM

IntelliStartDelivers additional yield in the early morning and the late evening.

IntelliStringUp to 80% reduction of cable loss.

Soladin web inverter

Mastervolt IntelliConcept: 5 to 10% more yield

74

meteocontrol is a technological leader and has been one of the most innovative service providers in the PV energy sector for more than 30 years.

Dates and factsThe company’s headquarters is in Augs-burg/Germany; further offices are located in Moers/Germany, Milan/Italy, Madrid/Spain, and Lyon/France. Its sister company, meteocontrol North America, was set up in 2010 for the North American market. 120 employees now work at these sites.

Independent consultingThe competence and experience of inde-pendent experts are indispensable in se-curing investments and minimizing risks. As a consultant and technical service pro-vider, meteocontrol supports PV projects with technologically leading solutions throughout the entire project life-cycle, such as reliable forecasts which incorpo-

meteocontrolIndependent Consulting and Intelligent Solutions for Your PV and Wind Projects

rate all relevant parameters and form the basis for sound and solid planning. An extensive range of services enables im-plementation and allows meteocontrol to ensure proper planned commissioning for large-scale projects. Since September 2012 meteocontrol is able to use a quali-fied rating system to measure the quality and the risk of yield loss of a PV project.

Competence in energy and weathermeteocontrol is able to draw on the most modern information technology and years of experience in monitoring renew-able systems: 31,000 PV systems with a total power of over 6.7 GWp are currently monitored. With a global market share of around 15% in professionally monitored systems, meteocontrol is a global market leader in this segment. meteocontrol’s product portfolio now offers monitoring solutions for every operation size – from private systems through to solar power plants. The recording and analysis of highly valid solarization data from satel-lite measurements enables precise en-ergy forecasts for PV systems. These solar power forecasts allow energy suppliers and network operators to precisely plan their network loads and their PV share of the energy mix.

meteocontrol GmbHAddress: Spicherer Straße 48 86157 Augsburg · GermanyPhone: +49 (0)821 34666-0Fax: +49 (0)821 34666-11Email: [email protected]: www.meteocontrol.com


Central recording of all system data

Business area: monitoring/supervision

75

Multi-Contact offers a broad range of products for the PV industry such as the original MC3 & MC4 connectors, solar cables, junction boxes and customized solutions, providing complete cabling solutions for components ranging from the panel to the inverter. The MC Multilam Technology ensures high efficiency and a long product life.

Often exposed to rough climates and de-manding environments, PV installations require resilient, efficient and long-lasting components, while costs and the time taken by certain processes need to be re-duced to keep the system profitable. With-out compromising quality, we offer time-saving connection solutions for all kinds of PV installations, from small off-grid sys-tems to large-scale PV power plants.

Quick installation and easy maintenanceWith our MC4 and MC4PLUS connec-tors, the entire installation can be cabled with a single system. The pre-assembled MC4PLUS (IEC 1500VDC, UL 1000VDC) is particularly suitable for module manufacturers and installa-tions with large cable cross sections. The original MC4 is available both pre-assembled and for on-site assembly. The new Y-test branch cables allow direct measuring under tension without inter-rupting the strings.

Reliable in all environmentsPV installations need to withstand UV radiation, wind, rain, snow and often dra-matic changes in temperature, requiring the reliability of all components. This is why MC subjects its products to vari-ous environmental tests: The MC4 con-nectors and Westlake junction box have successfully passed ammonia resistance tests simulating stable climate condi-tions over a 20-year period, as well as salt mist spray tests (DIN EN 60068-2-52:1996), proving them suitable for use in rural and coastal areas. The MC4 and MC4PLUS connectors conform to protec-tion categories IP65, IP67 and IP68 (1m/1h), while the Westlake is IP65 protected. All products are IEC and UL recognized.

Multi-Contact AGAddress: Stockbrunnenrain 8–12 4123 Allschwil · Switzerland Phone: +41 (0)61 306 55-55 Fax: +41 (0)61 306 55-56Email: [email protected]: www.multi-contact.com

Year founded: 1962

Multi-Contact AGThe Original MC3 & MC4 Connectors for Efficient PV SystemsMulti-Contact is one of the leading manufacturers of PV connector systems worldwide with more than 15 years of experience in the field, offering solutions for all kinds of PV installations.

Multi-Contact’s competence center for photovoltiacs in Essen, Germany

Business areas: module junction boxesconnection technology

PV connector MC4PLUS, designed for the use in high-volume cable assemblies

Type of MC Multilam, based on the torsion spring principle

PV-JB/WL junction box for crystalline modules

Multi-Contact AG headquarters, Switzerland

76

Nidec ASI was formed in December 2012 following the acquisition of Ansaldo Sis-temi Industriali Spa (ASI) by Nidec Corpo-ration. Over the past century and a half, ASI has specialized in providing innova-tive power control and system solutions that have satisfied hundreds of custom-ers worldwide. The company’s strength lies in working together with its custom-ers to develop innovative solutions that fully fit customers’ business and plant goals, allowing them to achieve a rapid return on investment.

Since the launch of its plug-and-play so-lution for large-scale solar plants, which gained the appreciation of the market due to its outstanding performance and reliability, Answer Drives GS SolarPower has been sold worldwide.

Nidec ASI S.p.A. Nidec ASI, a Destiny with Roots That Go Back More than 160 Years Nidec ASI operates in the solar industry with the complete dedication and customer orientation that result from its know-how and wealth of experience.

The Answer Drives GS SolarPower ensures extremely low harmonics, maximizing grid stability and ensuring near unity pow-er factor and a European Efficiency of over 98%. The Answer Drives GS SolarPower inverter family comprises four classes of inverters available in two versions – low voltage (400 V) for commercial installa-tions and medium voltage (10/15/20 kV) for utility applications. The inverters are CE marked according to EMC European Directive 2004/108/CE (compliance with EN 61000-6-3 and EN 61000-6-4) and Low Voltage Directive 2006/95/CE. The grid connection meets CEI 0-21, CEI 0-16 and Real Decreto RD1663/2000 standards. The interface is user-friendly and intuitive. In response to the high demand for solar plants in extremely hot climates, Nidec ASI offers a water-cooled version of its in-verter station.

About Nidec CorporationFrom its founding in 1973, the Nidec Group’s goal has been to become number one in electric drive solutions, while main-taining a strong focus on electric motors.

With a work force of approximately 98,000 and operations in more than 18 countries, Nidec, which is headquartered in Kyoto, Japan, has been quoted on the New York Stock Exchange since 2001.

Nidec ASI S.p.A.Address: Viale Sarca, 336 20126 Milan · ItalyPhone: +39 02 6445-1Fax: +39 02 6445-4401Email: [email protected]: www.nidec-asi.com


The Answer Drives GS SolarPower for

large-scale solar power stations

Part of a 2 MW PV plant in Italy

Nidec ASI S.p.A.

Business areas: invertershousingpower plant controlMLPMmonitoring/supervisionLOPconnection technologyplanning and grid integrationsoftware/IT

Robust containerized solutions for harsh environments

77

Protecting the network of cablesThe professional installation of our cable routing systems and connection and fas-tening systems ensures a fault-free, long-lasting connection between PV compo-nents. The OBO product range comprises cloes cable tray, wide span tray and mesh cable tray systems with the TrayFix mounting adapter for flat roofs.

Protection against surgesOur transient and lightning protection systems protect PV installations against damage and breakdowns caused by light-ning strikes and surges. The lightning and surge arrester up to 1000 V DC and the surge protective devices for AC and data solutions protect the investment against damages.

Protection against the spread of fireOur fire protection systems protect against the spread of fire, heat and smoke.

Combined protectionCombining our systems properly pro-vides all-round protection for small, large and free-standing installations alike.

OBO BETTERMANN GmbH & Co. KGCombined Protection with the ProtectPlus Program for Photovoltaic Installations Whether sun, rain, heat, cold, lightning or surges, a PV installation must be able to withstand many factors during its lifetime. OBO’s ProtectPlus systems provide effective protection and ensure reliable operation for many years.

ProtectPlus provides safe protection from environmental influences:• protects the electrical installation

against mechanical loads• protects the installation against direct

lightning strikes• protects the installation against

surges• protects the installation against fire

OBO offers solutions from external lightning and surge protection systems through to proper cable routing with cable support systems. OBO fire protec-tion systems fulfill the installation re-quirements.

Coordinated protection and the Protect-Plus system kit from OBO.

OBO BETTERMANN GmbH & Co. KGAddress: Hüingser Ring 52 58710 Menden · GermanyPhone: +49 (0)2373 89-0Fax: +49 (0)2373 89-238Email: [email protected]: www.obo-bettermann.com

Year founded: 1911 Employees: approx. 3,000

PV installation with insulated isCon® lightning conductor

Business areas: housing

LOP connection technology

OBO fire protection bandages

ProtectPlus – comprehensive pro-tection for PV systems

78

The family business employs more than 12,800 people worldwide and achieved a turnover of 1.59 billion euros in 2012. The headquarters are located in Blomberg (North Rhine-Westphalia) and Bad Pyr-mont (Lower Saxony). Seven companies belong to the Phoenix Contact Group Germany. In addition to the seven own production sites, the international group also includes almost 50 sales subsidiaries that are supplemented by 30 representa-tives in Europe and overseas.

In Germany, Phoenix Contact is repre-sented by a sales network of around 80 sales engineers located throughout the country. The automation specialist offers a product range which extends from special plug-in connector systems for distribution and field connection, to PV measuring modules and signal con-

Phoenix Contact GmbH & Co. KGComprehensive Solutions for Optimized PV Operation Phoenix Contact is a worldwide market leader for components, systems and solutions in the fields of electrical engineering, electronics and auto-mation. The automation specialist has established itself internationally as a reliable partner for the PV industry.

ditioners, as well as automation technol-ogy that includes full lightning and surge protection, and provides suitable and re-liable equipment for outdoor PV genera-tors and roof installations.

The comprehensive portfolio allows the implementation of turnkey solutions that make it possible to operate PV sys-tems even more profitably. This includes clever connection technology for time-saving assembly as well as innovative controllers for efficient system utiliza-tion.

The lightning and surge protection for PV systems increases availability and is therefore an essential part of planning new projects. Automatic monitoring by compact controllers provides users with a detailed overview of system power at any time. Special string monitoring modules measure the produced solar current. Via GPRS connections the controller trans-mits the data to operators anywhere in the world.

The portfolio is rounded off with a world-wide team of experienced specialists who help all international users with every matter concerning products from Phoenix Contact.

Phoenix Contact GmbH & Co. KGAddress: Flachsmarktstraße 8 32825 Blomberg · GermanyPhone: +49 (0)5235 3-00Fax: +49 (0)5235 3-41200Email: [email protected]: www.phoenixcontact.com

Year founded: 1923 Sales volume: 1.59 billion eurosEmployees: 12,800 (worldwide)

Solarcheck measures the electrical voltage and current of up to

eight strings.

Business areas: module junction boxespower plant controlmonitoring/supervisionLOPconnection technologysoftware/ITcommunication services

The plug-in VALVETRAB surge protection protects PV systems reliably against damage from lightning strikes, for example.

Sunclix plug-in connectors allow consistent and cost-effective cabling from the module to the inverter.

79

With a 40-year history as a leader in high-efficiency and high-density power supply products, Power-One has a broad range of experience that provides a strong foun-dation for innovation. Over the past four years, the company has continuously ex-panded its global footprint, operating manufacturing, sales, service and design facilities in Asia, Europe and North Amer-ica. To serve new and existing locations, Power-One opened additional manufac-turing and R&D facilities in Phoenix, Ari-zona, USA, and in Shenzen, China, in 2011. The company’s aim is to continuously im-prove its market penetration and perfor-mance throughout the world.

Broad portfolio for residential and commercial PV installationsIn addition to being among the first manufacturers to include three-phase string inverters in its portfolio, Power-One today offers one of the broadest portfolios in this segment, with products ranging from 6 kW to 27.6 kW. Striving to constantly improve the performance of its inverters, the company works to fur-ther increase the range of its three-phase AURORA TRIO inverter products for the residential and commercial sectors. The extensive portfolio also includes micro and single-phase inverters.

Power-OneAiming High with Innovative Solutions for Renewable Energy Power-One is the second largest designer and manufacturer of photovoltaic inverters worldwide. The company’s product portfolio includes inverters for residential applications as well as commercial or large-scale solar parks.

Best-in-class central inverters for large-scale PV projectsWith the demand for utility-scale solar parks shifting to the emerging markets, Power-One is prepared to meet their re-quirements with its central inverter solu-tions. Its AURORA ULTRA central inverter family is one of the best solutions in its class, offering a robust IP65 enclosure and a modular design concept with 690 Vac output to ensure easy maintenance and maximum energy harvesting.

Solutions for new applicationsPower-One is currently also looking into new markets, such as energy storage or smart house applications, and is using its long-standing experience to develop new best-in-class devices, thereby help-ing to ensure our future energy supply.

Power-OneAddress: 40 Calle Plano Camarillo, CA 93012 · USAPhone: +1 877 261-1374Email: [email protected]: www.power-one.com

Year founded: 1973 Employees: 3,300

Power-One Italy S.p.A.

Business areas: invertershousing

power plant controlmonitoring/supervision

storage technologies

Power-One Italy S.p.A.

TRIO-20.0-TLTRIO-27.6-TL

UNO-2.0-IUNO-2.5-I

ULTRA-1400-TL

80

Our companyOur goal is to maximize the yield of our customers’ photovoltaic installations through our award-winning and cost-effective inverters – starting from small roof installations to larger solar power plants. REFUsol is headquartered in Metzingen, Germany, and has interna-tional offices in Europe, Asia including China, Japan and India, and the USA, as well as sales and service partners in key strategic photovoltaic markets around the world.

Creative freedom and a passion for inno-vation are among our key corporate prin-ciples. REFUsol allows for creative space to drive superior engineering and our em-ployees are passionate about our products and the solar industry in general.

REFUsol GmbH High-Efficiency Inverters and Accessories for PV Installations REFUsol is a leading manufacturer of solar inverters. With over 48 years of experience in power electronics, REFUsol is one of the top providers of solar inverters globally and one of the fastest grow-ing companies in this field.

Our productsAs a central component in photovol-taic installations, solar inverters play a key role in energy conversion, ensur-ing profitability. Through our ongoing commitment to technical innovation, our inverters are leading the market when it comes to technology and ef-ficiency, communication and monitor-ing as well as easy installation and scalability. Whether sold under the REFUsol brand or via an OEM, REFUsol products are ranked top in Photon efficiency factor tests.

Our high-quality product portfolio in-cludes string, central and large inverters with a power range of 3.6 kW to 1.3 MW. Available globally, the range can be used in family homes as well as in large-scale solar parks and is suitable for operation in extreme geographical and climatically challenging environments, in an econom-ic and efficient way.

REFUsol GmbHAddress: Uracher Straße 91 72555 Metzingen · GermanyPhone: +49 (0)7123 969-0Fax: +49 (0)7123 969-165Email: [email protected]: www.refusol.com


REFUsol central inverter at 70 MW PV plant in Germany

REFUsol string inverters at 4.6 MW PV installation in Belgium

REFUsol training center in Metzingen

Business areas: invertersmonitoring/supervision

81

Building on decades of experience, Saft offers energy storage solutions ranging from kilowatts to megawatts to meet power and energy needs of any size.

Saft’s Li-ion energy storage systems are purpose designed to facilitate the ef-fective integration of both small and large-sized renewables, optimal use of transmission and distribution assets, streamlined smart grid management as well as greater options for demand side management.

Our storage systems will help you sepa-rate supply from demand, while signifi-cantly improving grid quality and reliabil-ity. Saft makes it easier for you to manage the challenges posed by renewables.

Our Intensium® Max containerized en-ergy storage units can smooth out in-termittent generation and reduce ramp rates for medium and large solar and wind power plants, ensuring a stable level of power output. Our higher-ener-gy systems also provide capacity firm-ing, making renewable energy a pre-dictable component of a grid operator’s electricity mix.

SaftLi-ion Energy Storage Systems for a New Energy Environment Saft’s battery systems meet every on-grid energy storage need, from grid stabilization in electricity production, to transmission and distribution networks, and on-site consumption in individual homes.

For on-site consumption applications, our experts can deliver customized bat-tery system kits, based on our standard Synerion® energy storage modules, for use in both OEM power system equip-ment or as stand-alone solutions.

Saft’s scope of supply extends far beyond merely providing Li-ion batteries. We in-tegrate our technology into complete energy storage systems that can include battery management, temperature man-agement and safety functions, as well as power management and power conver-sion functionalities.

Our world-class technology is supported by world-class manufacturing facilities, including one of the sector’s most techno-logically advanced lithium-ion battery fac-tories, located in Jacksonville, Florida (USA).

SaftAddress: 12, rue Sadi Carnot 93170 Bagnolet · FrancePhone: +33 (0)149931918Fax: +33 (0)149931964Email: [email protected]: www.saftbatteries.com

Year founded: 1918 Employees: 4,000 (present in 18 countries)

Saft’s lithium-ion battery factory in Jacksonville, Florida (USA)

Business area: storage technologies

Intensium® Max containers:

Over ten units in the MWh or MW

class were shipped in 2012.

Synerion Storage System (for example: stand-alone, 48 V to 4kWh):

Hundreds of units were shipped in 2012.

82

Schneider Electric provides bankable photovoltaic solutions for installations of any size, together with long-term sup-port from a global company with over 175 years of experience. Schneider Electric products are present at every link in the energy chain, helping customers secure the most efficient solar harvest possible from their installations thanks to quali-fied and reliable integrated solutions.

For utility-scale and large commercial in-stallations, Schneider Electric provides in-tegrated solutions including a PV Box, ar-ray boxes, monitoring & control, and grid connection substations. The PV Box is a factory integrated, tested & validated plug & play power conversion system that, in addition to comprising grid-tie inverters, a DC combiner box, step-up transformer, medium voltage switchgear and other ac-cessories, is adapted to meet local installa-tion conditions. Other items can be added to the package, including the Conext Con-trol monitoring and control solution, cli-mate controls or security equipment.

Schneider Electric The Global Specialist in Energy Management As a global specialist in energy management with operations in more than 100 countries, Schneider Electric is focused on making energy safe, reliable, efficient and green.

For the residential and commercial mar-kets, Schneider Electric offers DC/AC kits and grid-tie, single-phase and three-phase inverters ranging from 3 kW to 20 kW. All inverters are reliable, flexible and easy to install. Backed by the com-pany’s global service infrastructure and its expertise in energy management, Schneider Electric inverters are the invert-ers you can trust for quality and reliability.

The Schneider Electric solution for off-grid solar and back-up power installa-tions includes inverter/chargers, charge controllers (with or without MPPT track-ing), DC/AC breakers and related acces-sories. The inverter/charger has unsur-passed surge capacity to prevent drops during power surges. It can be configured for single- and three-phase installations up to 36 kW and allows dual AC inputs for the grid and a generator.

For more information about Schneider Electric, please visit www.schneider-electric.com/solar

Schneider Electric SAAddress: 35 rue Joseph Monier 92506 Rueil-Malmaison · FrancePhone: +33 (1)14 1297-000Fax: +33 (1)14 1297-100Web: www.schneider-electric.com/solar

Year founded: 1836Sales volume: 24 billion euros (2012)Employees: > 140,000

Solution for residential and small commercial buildings

6 MW power plant in Osiyan (India)

Solution for large commercial

and PV power plants

Business areas: invertersconnection technologyhousingcharge regulatorsmonitoring/supervision

83

Business areas: power plant control

monitoring/supervisionplanning and grid integration

software/IT

How can our energy generation be shaped in a sustainable and profitable way? Providing the answers to this ques-tion has been the constant focus of all our operations for 36 years, ever since graduates from the Technical University of Berlin founded the Wuseltronik col-lective at the end of the 1970s and devel-oped their initial visions for the system-atic and cost-efficient use of renewable energy.

The pioneering spirit of those days is very much alive at the present-day head-quarters of skytron® energy in the Berlin-Adlershof Science and Technology Park. Then as now, we consider working closely with scientific research as well as focus-ing on practical solutions to be essential in this fast-growing industry.

Our long-term experience ensures reli-able plant monitoring at PV power plants throughout the world. Our power plant control technology and control room software now permanently watch over more than 3.7 GWp of installed PV out-put. We customize each installation to match the configuration of every indi-vidual plant – from precise string-current measurements right through to the con-

skytron® energy GmbH OUR INNOVATION FOR YOUR BENEFIT How long does it take to find a coin on a soccer field? Even on a surface area of several soccer fields, you should lose neither time nor money.With skytron® energy – Protected investments. Secured yields. Maximized profits.

trol room presentation, thus allowing for effective supervision of your remote as-sets. Moreover, skytron® energy provides a complete O&M solution.

Our system is compatible with all stan-dard inverters on the market, allowing it to be readily adapted to fit your facili-ties – and to expand with them. In this way your investment costs are protected and the cost-effectiveness of your plant is maintained.

The visions of the early days have been transformed into cutting-edge compo-nents for PV power plants in the MW sec-tor, which are exactly what the market is looking for. Ensuring your success is at the heart of what we do.

skytron® energy GmbHAddress: Ernst-Augustin-Straße 12 12489 Berlin · GermanyPhone: +49 (0)30 688 3159-0Fax: +49 (0)30 688 3159-99Email: [email protected]: www.skytron-energy.com


ArrayGuard® FH combiner box with single PV string protection, which monitors string currents

at 100 ms

ArrayGuard® FH fuse holders for easy-to-handle fuse replacement – fuses on each single PV string

PVGuard® supervision platform – quick overview of all plants and comparison of important real-time data

84

Independence from rising electricity prices – with innovations from SMA

SMA inverters as intelligent system managersInverters convert direct current gener-ated by PV cells into grid-compatible alternating current so it can be used by system operators or fed into the util-ity grid. As intelligent system managers, inverters also control PV arrays and util-ity grids. SMA offers an inverter solution for all module types and performance ranges: from small residential PV systems to large-scale PV plants, as well as from grid-connected systems to off-grid and backup systems.

SMA Solar Technology AG Energy that Changes The SMA Group is the global market leader in solar inverters, an essential component of every PV system, and an energy management group that offers innovative key technologies for power supply systems of the future.

Innovative key technologiesIntelligent energy management in the home is an integral component of a de-centralized, renewable energy supply. With SMA Smart Home, PV system op-erators can optimize on-site consump-tion and gain independence from rising electricity prices.

Intelligent energy management in the householdThe Sunny Home Manager is the control center of the SMA Smart Home. The de-vice learns the household’s typical con-sumption behavior and combines this in-formation with PV forecast data for solar power generation to ensure optimized consumption.

For greater independence from rising elec-tricity prices, SMA offers a highly flexible battery inverter – the Sunny Island. Solar energy can be buffered and used after sunset. The device is suitable for all system sizes, PV inverters and battery types.

SMA is launching Sunny Boy 5000 Smart Energy, as the first mass-produced, wall-mounted PV inverter with an integrated battery, this new model will prove par-ticularly valuable for residential PV sys-tems with outputs of up to 5 kW.

Intersolar 2012: SMA’s Sunny Boy 5000 Smart Energy

is the first wall-mounted mass-produced PV inverter with an

integrated battery.

SMA Smart Home: independence from rising

electricity prices coupled with convenience

Sunny Home Manager is the control center of SMA Smart Home.

Business areas: inverterspower plant controlMLPMmonitoring/supervisionconnection technologyplanning and grid integrationsoftware/ITcharge regulatorscommunication services

SMA Solar Technology AGAddress: Sonnenallee 1 34266 Niestetal · GermanyPhone: +49 (0)561 9522-0Fax: +49 (0)561 9522-100Email: [email protected]: www.SMA.de

Year founded: 1981Sales volume: 1.5 billion euros (2012)Employees: > 5,000

85

The products we have developed at Solare Datensysteme GmbH are highly user-friendly, requiring zero software installation. Our products scale from small residential up to large commer-cial applications. Solar-Log™ is compat-ible with most major inverter manufac-turers on the market. With our “Easy Installation” firmware we have auto-mated the inverter detection process as well as the Solar-Log™ WEB (if used) provisioning process.

In addition to monitoring and efficiency control, users have the capability to ana-lyze their data either on-site or via the in-ternet. This is accomplished by means of attractive graphical data representations, as well as informative data tables. Con-trol your PV system at any time, wherever you are in the world, using Solar-Log™ APP for Android, iPhone and iPad. Besides cable connectivity, Solar-Log™ also offers wireless connectivity using GPRS, WLAN and Bluetooth. Solar-Log™ even offers a solution for monitoring, controlling and optimizing one’s own solar power con-sumption as well as Power Management and cos ϕ control.

Solare Datensysteme GmbH Everything You Need to Monitor Your Photovoltaic Plant Solar-Log™ represents PV plant monitoring and management. The Solar-Log™ monitoring system, manufactured by Solare Datensysteme GmbH, has been on the market since 2007. As a market leader, we equip more plants than any other monitoring organization.

Solar-Log™ is just as suitable for plants with one inverter as it is for large plants with central inverters and complies fully with technical regulations. For the moni-toring of individual strings in very large plants, we also have a high-quality string connector box in our product portfolio.

The Solar-Log™ WEB Commercial Edition web solution offers portal operators a comprehensive plant maintenance in-terface. The ability to carry out remote configuration and maintenance can save work from having to be performed on site. Error messages are clearly dis-played in an overview screen and can be processed using the integrated ticket system and error analysis tool.

Solare Datensysteme GmbHAddress: Fuhrmannstraße 972351 Geislingen-Binsdorf · GermanyPhone: +49 (0)7428 9418-200Fax: +49 (0)7428 9418-280Email: [email protected]: www.solar-log.com


Solar-Log™ WEB Commercial Edition ensures reliable plant monitoring and quick repairs in case of failures.

Business areas: power plant control

monitoring/supervision planning and grid integration

software/IT

A worthwhile alternative: direct utilization of self-generated PV energy

Graphic Solar-Log1000

86

High-quality products made in Switzer-land have enabled SolarMax to grow from a start-up into one of Europe’s leading in-verter manufacturers.

Thanks to technical know-how, broadly supported knowledge, and more than 20 years of experience in developing inverters SolarMax is able to produce high-quality products. SolarMax inverters are among the industry’s best, offering high efficiency, an intelligent cooling concept, an attrac-tive, easily-mounted casing and a user-friendly graphics display. All inverters are extremely robust and absolutely reliable – and at a convincing price/performance ratio. SolarMax has the right inverter for every application – from photovoltaic sys-tems on single-family homes whose kilo-watt output is modest, to the solar power plants whose output is measured in mega-

SolarMaxSwiss quality by Sputnik Engineering With its SolarMax brand, the Swiss company Sputnik Engineering AG has focused on solar energy since 1991 and has been a pioneer in the industry ever since. The company develops, produces and sells grid- connected inverters for every solar system.

watts. Furthermore, the product family comprises a series of communication and monitoring solutions, as well as software tools developed for specific assignments.

Service at its very bestHighly qualified technicians are on hand to advice SolarMax customers on the phone. The service team can trouble-shoot and correct malfunctions either by remote di-agnosis or by sending a technician directly to the site. SolarMax carries out specifical-ly designed training measures and courses for its clients – either at its own locations, or directly on-site at the customer’s prem-ises. The SolarMax experts are always available for their customers with advice and support. All requests are answered rapidly, frankly and directly, because SolarMax believes in solid customer ser-vice and long-term customer relations.

Swiss quality with high efficiency: SolarMax inverters set standards in terms of quality, reliability, and maximum yields.

Business areas: invertersmonitoring/supervision

Sputnik Engineering AGAddress: Länggasse 85 2504 Biel/Bienne · SwitzerlandPhone: +41 32 346 56 00Fax: +41 32 346 56 09Email: [email protected]: www.solarmax.com

Year founded: 1991Employees: 360 (2012)

87

In the three market segments, PV grid connected, PV off grid and solar thermal, the Steca brand is synonymous with innovation and vision. Be it conception, development, production or marketing, we are committed to the highest quality standards. Our focus lies on made-to-measure solutions for the effective utilization of solar radiation. Further-more, Steca continually examines the technologies it has developed with a view to simple operation and, conse-quently, usability for the wide base of the population – worldwide.

PV grid connectedTogether with our range of accessories, StecaGrid inverters represent an innova-tive family of inverter solutions for grid-connected solar power systems. Whether being used in a small solar power system for a single family home, or an elabo-rate combined solution for an industrial complex, Steca grid-feeding inverters all have one thing in common: They offer the highest performance along with maxi-mum flexibility and ease of use.

Steca Elektronik GmbH Steca Solar Electronics – Products and Solutions for anEcological Future As a leading supplier of products for the solar electronicsindustry, Steca sets the international standard for theregulation and control of solar energy systems.

PV off gridTwo billion people in rural areas still have no access to an electricity grid. Steca has set itself the target of improving the qual-ity of life of these people. To this end, Steca develops and manufactures top-quality products, which, thanks to their long life-time, ensure extremely low costs. Today, modern and professional electricity sup-plies are necessary in every part of the world. For these supplies, the focus is on high industrial demands, flexibility, envi-ronmental sustainability and reliability. As an expanding company, Steca Elektronik will continue to bank on Germany and Bavaria as an energy industry center: With a total of 650 employees, the company currently manufactures products for an ecological future on a production area of 29,000 m2.

Steca Elektronik GmbHAddress: Mammostraße 187700 Memmingen · GermanyPhone: +49 (0)8331 8558-0Fax: +49 (0)8331 8558-132Email: [email protected]: www.steca.com


Headquarters of Steca Elektronik GmbH in

Memmingen

The Steca coolcept inverter has set a new world record in inverter efficiency.

The new Steca Tarom 4545: innovative andfunctional design

Electronics made in Memmingen – Bavaria


storage technology charge regulators

monitoring/supervision software/IT


88

+

-

89

The Publishers

+

-

90

Since 1998 the Berlin-based company has been providing clients with exper-tise and professional service in the fields of engineering, conference organization and publishing.

EngineeringThe engineering division generates up-to-date knowledge, which is then pre-pared for and presented to manufac-turers, wholesalers, planners and trade professionals in a targeted, project-specific manner. Whether in the area of photovoltaics, solar thermal technology, heat pumps or pellets, clients receive ex-pert and reliable support for reporting, large-scale solar projects, technical docu-mentation, training, expert hotlines and customer service.

ConferencesThe conference division focuses on or-ganizing high-quality industry events for decision-makers both in Germany and abroad. These events are sub-stantiated, relevant to the market and customer-oriented. Using specialist lectures and topical panel discussions,

Solarpraxis AG Engineering, Conferences and Publishing for Renewable Energies Solarpraxis AG is one of the leading knowledge service providers in the renewable energy sector.

the division provides practical knowl-edge on market performance, finance and politics. The events are organized in Europe, Asia, North America and in the Middle East.

PublishingThe third and final component of the company’s service portfolio is its publish-ing department, which boasts two inter-national brands, pv magazine and RENI | Renewables Insight.

Since its initial publication in 2008, pv magazine has evolved into the top international photovoltaics magazine for decision-makers. With a global, Chi-nese and German edition, pv magazine is expanding its position as a global knowledge provider. The media portfolio includes print magazines, e-papers, web-sites and daily newsletters.

The multilingual industry reports under RENI | Renewables Insight respond to the demand for high-quality industry and technology guides. In collaboration with professional associations, information on technology and markets is provided and companies are given an opportunity to communicate expert knowledge about their products and services.

SOLARPRAXIS AGAddress: Zinnowitzer Straße 1 10115 Berlin · GermanyPhone: +49 (0)30 726296-300Fax: +49 (0)30 726296-309Email: [email protected]: www.solarpraxis.de

Year founded: 1998Sales volume: 6.9 million eurosEmployees: 70

The engineering department generates up-to-date knowledge.

B2B magazines and industry guides: The publication range of

Solarpraxis includes the complete spectrum of renewable energies

Solarpraxis conferences: valued industry platforms

Business area: communication services

91

We provide profound market insights together with top-quality contacts to German industry associations, political decision-makers and the press.

Public relationsSunbeam supports you in establishing and expanding your communications with customers and the general public. We offer high-quality consultancy servic-es for companies, associations and minis-tries, and provide strong conceptual skills for the development of PR campaigns.

New mediaSunbeam plans and implements your website project using barrier-free, user-optimized designs. We offer extensive expertise in TYPO3, one of today’s leading open source content management sys-tems for websites. Members of our team have published widely-distributed and much-quoted books on the design and implementation of websites.

Sunbeam CommunicationsCommunications for Renewable EnergiesSince 1998, Sunbeam has offered technical expertise combined with professional communications services for the renewable energy market.

Communication designOur designers develop key elements for visual communication between your company and your customers. Our tech-nical illustrations allow a clear visual presentation of your products. We spe-cialize in editorial design for high-quality print products including catalogs and journals.

Sunbeam GmbHAddress: Zinnowitzer Straße 1 10115 Berlin · GermanyPhone: +49 (0)30 726296-300Fax: +49 (0)30 726296-309Email: [email protected]: www.sunbeam-communications.com

Year founded: 1998 Employees: 19

We combine high-quality communications with expertise in technologies and markets in the field of renewables.

Business area: communication services

Information campaign “Heating Today with

Solar Energy”

As a full-service partner we support you in managing your cross-media communications.

SolarwärmeInformationen für Vermieter

Solar – so heizt man heute

92

Important noticeThis brochure, all parts thereof and the website are protected by copyright. The reproduction, alteration and any other type of use of the brochure or parts thereof, except for purely private pur-poses, is prohibited except with the prior approval of Solarpraxis AG. This shall ap-ply in particular to reproduction/copies, translations, microfilming and storage in electronic systems.

The citing of text by media representa-tives and political decision-makers is expressly desired and does not require prior approval, provided that the source of any text used is also cited.

The texts and illustrations in this brochure were produced with the greatest possible care and to the best of the author’s knowledge. As errors cannot be ruled out and both texts and illustrations are subject to change, we draw your attention to the following: Solar praxis AG gives no guarantee with regard to the timeliness, accuracy, com-pleteness or quality of the information provided in this brochure. Solarpraxis AG accepts no liability for damages, material or non-material, which are incurred through the use or non-use of the information provided or which are caused directly or indirectly by the use of erroneous and incomplete informa-tion, except where deliberate or grossly negligent culpability may be proven. Company entries are the sole responsi-bility of the respective company.

Picture creditsCOVER See inside front coverINDUSTRY See captions Unless otherwise stated: Tom BaerwaldCOMPANIES, PUBLISHERS The illustrations were supplied by the company/association under whose heading they are published, unless otherwise stated.

Infographics and tables: © Solarpraxis AG, unless otherwise stated

“The Industry” sources

DGS Landesverband Berlin-Brandenburg: Leitfaden Photovoltaische Anlagen, 4th edition, Berlin 2010Konrad Mertens: Photovoltaik, Carl Hanser Verlag, 1st edition, Munich 2011photovoltaik. Das Magazin für Profis, 01, 04, 05, 06, 07, 08, 10/2012Volker Quaschning: Regenerative Energiesysteme, Carl Hanser Verlag, 5th edition, Munich

Important Notice, Picture Credits & Sources

92

93

Published bySolarpraxis AG Zinnowitzer Straße 1 10115 Berlin Germany

Phone: + 49 (0)30 72 62 96 - 300Fax: + 49 (0)30 72 62 96 - 309Email: [email protected]: www.solarpraxis.com

Responsible under the German Press Act: Karl-Heinz Remmers

© March 2013, Solarpraxis AG

Idea and concept Solarpraxis AG

Project management/Editor “The Industry” Solarpraxis AG/Dr Roland Ernst

Editor “Companies” Solarpraxis AG/Ute Bartels

Editorial assistance Katharina Malchow, Sandra Steinmetz

“The Industry” authors Dr Detlef Koenemann, except p. 27 (“A view on the United States”) – 29: Ucilia Wang Ch. 10 (“Market Situation and Forecasts”): Ash Sharma, Glenn Gu, Sam Wilkinson, Henning Wicht (iSuppli)

“The Industry” technical proofreading Christian Dürschner

“The Industry” translation Übersetzungsbüro Peschel

Layout & composition Sunbeam GmbH/derMarkstein.de

Photo editor & image processing Tom Baerwald

Infographics Sunbeam GmbH/Kay Neubert derMarkstein.de

Website design by Sunbeam GmbH

Printed by Druckhaus Berlin-Mitte GmbH

Booklet website www.pv-system-tech.com

Legal Information

94

PV Module and PV Power Plant Workshop – China 2013

Shanghai, China | September 2013

Quality for Photovoltaics 2013 Berlin, Germany | 12 September 2013

Solar meets Glass Dusseldorf, Germany | 09 – 10 October 2013

PV Power Plants – USA 2013 California, USA | November 2013

Solar Industry Summit – Middle East 2013

Dubai, United Arab Emirates | 06 November 2013

14th Forum Solarpraxis Berlin, Germany | 21 – 22 November 2013

PV System Technology Forum – EU 2014

February 2014

PV Power Plants – EU 2014 March 2014

PV Project Implementation Conference – China 2014

Shanghai, China | March 2014

Thin-Film Industry Forum 2014 Berlin, Germany | April 2014

Energy Storage – International Summit for the Storage of Renewable Energies

Dusseldorf, Germany | 01 – 02 April 2014

Best practice and expertise since 1998

www.solarpraxis.compowered by

Your gateway to the solar sector

95

PV Module and PV Power Plant Workshop – China 2013

Shanghai, China | September 2013

Quality for Photovoltaics 2013 Berlin, Germany | 12 September 2013

Solar meets Glass Dusseldorf, Germany | 09 – 10 October 2013

PV Power Plants – USA 2013 California, USA | November 2013

Solar Industry Summit – Middle East 2013

Dubai, United Arab Emirates | 06 November 2013

14th Forum Solarpraxis Berlin, Germany | 21 – 22 November 2013

PV System Technology Forum – EU 2014

February 2014

PV Power Plants – EU 2014 March 2014

PV Project Implementation Conference – China 2014

Shanghai, China | March 2014

Thin-Film Industry Forum 2014 Berlin, Germany | April 2014

Energy Storage – International Summit for the Storage of Renewable Energies

Dusseldorf, Germany | 01 – 02 April 2014

Best practice and expertise since 1998

www.solarpraxis.compowered by

Your gateway to the solar sector

Solar Solutions from Trusted Experts

IHS Solar solutions combines the products, services, and expertise from the IHS acquisitions of three leading research companies and provides forecasts for market demand, technology, and supply chain analysis to advance clients’ strategies in global solar markets.

To learn more: www.ihs.com/solar | [email protected] | +44 (0)1933 402255

9119_0313PB

Bankability of PV Projects Environmental impact studies (eg. glint and glare reports) Grid connection consulting Yield assessment reports Quality assurance reports

Our independent third party reports are accepted by all major European banks.

For further information please contactMr. Christian Steinberg, +49 (0) 30-726296-342, [email protected]

www.solarpraxis.com/engineering

Phot

o: To

m B

aerw

ald

96

p h o t o v o l t a i c m a r k e t s & t e c h n o l o g y

Markets & TrendsSaudi Arabia: Big plans in store. But, solar players await detailsbefore making decisions. Page 28

Storage & Smart GridsLithium: As storage demand grows, bottlenecks in this raw material’ssupply look imminent. Page 92

Industry & SuppliersThin film: Erosion of competitive advantage. Thin film makers seek ways to stay afloat. Page 62

Phot

o: A

123

Syst

ems

Phot

o: S

olyn

dra

Phot

o: M

icha

el U

rban

Why waste this space?Photovoltaic potential on landfills. Page 74

Phot

o: H

DR,

Inc.

07 | 2012 | 78538

Print or Digital Subscription Select the one that best suits your needs.

Both include:• globalFITdata• marketoverviewsand• onlineaccesstofullmagazinearchive

www.pv-magazine.comEmail: [email protected]

Subscribenow!

Cover images

Front

Main image Vented stationary lead-acid battery with a liquid electrolyte. The tubular plates technology is designed to result in a large number of cycles during the batteries’ lifetime. (Photo: Tom Baerwald/HOPPECKE Batterien GmbH & Co. KG)

Small images, f.l.t.r. Taking measurements using a thermal imaging camera (Photo: Tom Baerwald/Lebherz) Central inverter in a ground-mounted installation (Photo: Tom Baerwald) String inverter in an electromagnetic compatibility (EMC) test chamber (Photo: SMA Solar Technology AG)

Back

Climate chamber test to ensure that inverters withstand extreme temperature variations (Photo: SMA Solar Technology AG)

Top information for yourvisit in Munich, Germany

The World´s Largest Exhibition for the Solar IndustryMesse München, Germany

Intersolar Europe gives you an insider advantage on cutting-edge information about the dynamic markets of the solar industry

Connect with 1,500 international exhibitorsLearn everything about the latest innovationsKeep up with future trends for continued business successGet inspired!

AZISE2013_IntverterPV_210x297.qxp:Layout 1 07.03.13 10:59 Seite 1


Industry Guide 2013


Industry Guide 2013

recommended by

“Inverter, Storage and PV System Technology” takes a close look at the electrical components of the PV system and its interactions, presents the latest technical developments, and gives an overview of market conditions.

Corporate portraits of international companies round off this comprehensive industry guide on PV system technology.

www.pv-system-tech.com

climate-neutral

Date post:	26-Nov-2015
Category:	Documents
Upload:	ahmetgumus1903
View:	240 times
Download:	6 times

Inverter, Storage and PV System Technology Industry Guide 2013

Documents