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Transforming wind into an assetHow reliable turbines became robust investments

From reliable turbines... In the quarter-century since Siemens installed the world‘s first offshore wind power plant off the coast of Denmark, the capacity of offshore turbines has increased more than tenfold. Offshore wind is now established as a viable energy source and a reliable way to achieve emissions targets. Once financed almost exclusively by utilities, offshore is now acknowledged by bankers as a dependable asset. For many investors, the question is no longer whether to invest in offshore, but rather which offshore supplier will make the most reliable partner long term.

Offshore wind power comes of age

...to robust investmentsHaving installed the first-ever offshore wind turbines at Vindeby in 1991, Siemens was the first company to face – and overcome – the challenge of maintaining and improving unproven offshore technologies. By taking the lead in maturing offshore wind power products and services, we gradually acquired unparalleled experience and expertise – to the benefit of investing partners.

With its unique experience in the offshore wind industry and its innovative mindset, Siemens offers a comprehensive portfolio of solutions that transforms the wind into an asset. An asset for profitable investments for our partners that will provide clean energy for generations to come.

Intro | Transforming wind into an asset

“ A gram of experience is worth a ton of theory.”

U.K. Prime Minister Robert Gascoyne-Cecil

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Excellence at every stage

Despite the difference in scale between the first, 450 kW offshore wind turbines that Siemens installed in 1991 and the multi-megawatt models currently deployed offshore, many offshore industry standards can be traced back to that first site at Vindeby.

Indeed, Siemens engineers used the experience gained from this project to further improve design, sourcing, and manufacturing. A three-stage manufacturing cycle evolved that still continues from platform to platform. Together with a rigorous testing regime and product platform strategy, this cycle lays the groundwork for product maturity and reliability.

Stage 1: Reliable technology Siemens builds reliability into every wind turbine platform by reusing proven components, design principles, and technologies from one product generation to the next. The more components from the previous generation, the more predictable the performance and service with the new platform.

Stage 2: Reliable supply chainSuccessful sourcing requires intensive monitoring of the components provided by suppliers and subsuppliers. The tireless efforts of Siemens‘ quality-control teams are characterized by a dedication to always complying with Siemens‘ quality standards.

Stage 3: Reliable assemblyDrawing inspiration from carmakers, in 2010 Siemens took the first step toward industrializing wind turbine manufacturing, with the introduction of moving-line assembly. This ensures higher and more consistent quality standards and enables more efficient use of the company‘s manufacturing facilities. With the introduction of the new factories in Hull (2016) and Cuxhaven (2017), the final step in industrializing offshore through the modularized assembly process of the direct drive platform is complete.

Onshore Geared

Offshore Geared

Onshore Direct Drive

Offshore Direct Drive

Design

Sourcing

Assembly

Every Siemens platform builds on the strengths of its predecessor, from the Onshore Geared platform introduced in 1999 to the current Offshore Direct Drive platform.

Transforming wind into an asset | Turbine reliability Turbine reliability | Transforming wind into an asset

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Higher and more consistent offshore wind speeds increase returns for investors and operators alike, but they also present significant challenges. The sheer scale of offshore maintenance operations makes investment safeguards such as thorough testing all the more crucial for offshore wind turbines.

Exceeding expectationsAs the first company to introduce an all-embracing test program for offshore wind turbines, Siemens offers its partners unrivaled experience in test procedures. To deliver the consistent quality that Siemens’ customers expect, these procedures have been developed even further than the general requirements specified by the industry ’s certifying bodies.

Pre-prototype testingTurbine testing comprises three main stages: structural, mechanical, and electrical testing. Before the first prototype turbine can be erected in the field, a certification authority must verify its overall structural capacity.

Whereas certification of structural safety and electrical systems is a legal requirement, validating the robustness of other systems and components effectively remains optional. To help safeguard our partners’ investments, Siemens also rigorously tests materials, major components, and modules prior to prototype testing.

Prototype testingPrototype turbines provide valuable operational experience. They help to verify initial calculations from the design stage and are essential to further research and development. Prototype test results feed into the verification and implementation of service programs as well as solutions for new turbine designs.

Material, component, and module testing take place at Siemens’ dedicated test sites in Aalborg and Brande, both in Denmark. Together, they form the largest wind turbine testing facility in the world.

Pioneering procedures2004 saw two milestone achievements for the offshore sector: the launch of the first dedicated offshore wind turbine platform (the Siemens Offshore Geared platform) and the introduction of the first fully fledged offshore test program. Siemens’ partners were the exclusive beneficiaries of both.

In response to the increasing importance of offshore wind power and the challenges of the offshore environment, Siemens introduced a structured approach to testing. Blades, bearings, gearbox, and other major components were pushed to their limits and the first Offshore Geared turbine – the SWT-3.6-107 – was subjected to more than 200 separate, highly accelerated lifetime tests. These procedures have been repeated for every new turbine design since.

Uncompromising testing...

...far beyond industry standards

Tested at every level

Step 1

Step 2

Step 3

Step 4

Material test

Component test

Module test

Prototype test

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3

2

1

Transforming wind into an asset | Turbine reliability Turbine reliability | Transforming wind into an asset

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1991 Vindeby 11 turbines 450 kW

450 kW Height: 54 m Rotor diameter: 37 m Output: 0.45 MW

G2 platform (now the Onshore Geared platform)Height: 100 – 125 m Rotor diameter: 82 – 101 m (offshore) Output: 2.0 – 2.3 MW

2003 Nysted72 turbines 2,300 kW

2007 Burbo Bank 25 turbines 3,600 kW

2012 London Array Limited 175 turbines 3,600 kW

2016 Godewind I & II 97 turbines 6,000 KW

Offshore Direct Drive platformHeight: 175 – 185 m Rotor diameter: 120 – 154 m Output: 6.0 – 8.0 MW

2000 Middelgrunden 20 turbines 2,000 kW

2002 Samsø 10 turbines 2,300 kW

Offshore Geared platformHeight: 130 – 155 m Rotor diameter: 107 – 130 m Output: 3.6 – 4.0 MW

From world’s first to world-class

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Transforming wind into an asset | From world’s first to world-class From world’s first to world-class | Transforming wind into an asset

Because rust never sleeps Jens Thomsen came to Siemens from the maritime industry in the early 1990s, to work as a design technician on the Vindeby turbines. From his maritime experience, he was in no doubt about the scale of the challenges ahead. For example, the salty and humid sea air makes conditions ideal for corrosion, a major cause of structural damage, short circuits, and leakages. In the mind of the young engineer, the decision to pursue a career installing high-tech mechanical structures in the hostile offshore environment was as brave as it was potentially fulfilling.

While rigorous testing drives the development of ever more powerful platforms, offshore experience is the bedrock on which investment robustness is built. Starting in 1991, Siemens has a track record that no other provider can match.

1991. The Vindeby Wind FarmInstalling the world’s first offshore wind power plant was a move into uncharted waters, in more ways than one. New procedures were required for installation, operations, and maintenance. What’s more, offshore experts were in short supply. In 1991, Siemens had just 11 wind power engineers. Nevertheless, this small team of specialists was able to tailor onshore technology to the demands of offshore and make the groundbreaking first deployment a success.

Onshore technology thrives offshoreOn July 11, 1991, Vindeby offshore wind farm delivered its first power to the grid – a historic day in the renewable energy industry. With a combined capacity of 5 megawatts, its 11 turbines exceeded all expectations, consistently producing 20 percent more electricity than equivalent onshore wind power plants.

After more than two decades of successful operation, the Vindeby turbines are about to be dismantled by their owner, DONG Energy. However, these five machines will always mark the beginning of an unrivaled renewables growth story for the benefit of generations to come.

History in the making

Offshore’s most experienced engineers

Undaunted, Jens devised an innovative, twofold strategy to minimize the risk of corrosion. First, he had specially developed seals and dehumidifiers installed in the tower and nacelle. This prevented salt from entering the structure and kept humidity in check inside the turbine. Then, to complete the corrosion-control process, his team treated every metal surface with a protective paint developed in cooperation with Danish coating specialists Hempel.

This solution was designed to last 20 years and in 2011 tests proved the turbines were indeed still corrosion-free. Whereas after 25 years of uninterrupted operation the Vindeby turbines face retirement, Jens Thomsen remains one of Siemens’ most senior – and expert – offshore engineers.

“My goal is to cut costs for customers by providing state-of-the-art solutions.”

Jens Thomsen

1991

11 turbinesTotal number of Siemens turbines installed offshore

Transforming wind into an asset | Turbine technology Turbine technology | Transforming wind into an asset

Vindeby Offshore Wind Farm

Turbine type Bonus 450 kW

Farm size 11 turbines

Capacity 4.95 MW

Location Lolland, Denmark

Owner DONG Energy

The Bonus 450 kW wind turbine at a glance• Three-bladed upwind turbine • Geared asynchronous generator• Stall fixed pitch and fixed speed • Directly connected to the grid

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1999. The G2 platformBy the late 1990s, Siemens had acquired nearly a decade of in-depth offshore expertise. The success of the Vindeby wind farm project underlined the importance of two key features that differed significantly from onshore operations: lightning protection and serviceability.

Enhanced lightning protectionIf lightning passes through the inner workings of a wind turbine, the result is immediate failure. The lightning protection system installed at Vindeby had proved its worth for these relatively small turbines, but an even more robust system was required to protect the larger rotor blades of higher-capacity models that would attract more frequent lightning strikes. The solution was an enhanced system that integrated lightning receptors within the structure of the blades. These controlled where lightning struck the turbine while insulated circuits channeled the current down to the sea.

Learning from the 450 kW platform design used at Vindeby, over the following decade Siemens continued to evolve its platform and service portfolio, which did not distinguish between offshore and onshore platforms until the introduction of the Offshore Geared platform.

1995. The 600 kW platformThe first 600 kW platform featured a reinforced bedplate and one main bearing instead of the two bearings on the 450 kW platform. The stationary drivetrain design was discarded in favor of a new design with a rotating main shaft. The gearbox was moved further back and separated from the main shaft by a coupling, while the cooling system was optimized to regulate the temperature of the gear oil. In addition, the 600 kW introduced a new yaw system based on an innovative slide-bearing design with claws.

1996. The 1,000 kW platformThe 1,000 kW platform formed the basis of four different wind turbines: the 1,000 kW, the 1,300 kW, the 2,000 kW, and the 2,300 kW. It also prepared the way for a quantum leap in turbine design. The next generation of turbines would adapt to the varying needs of the grid by replacing COMBISTALL® pitch control with Variable Speed, made possible by the NetConverter® technology that made its debut on the next platform – the G2 platform (now the Onshore Geared platform).

From kilowatts to megawatts

Superior serviceabilityThe wind is significantly colder at hub height than at ground level so the Vindeby turbines featured a movable shield to shelter service technicians while they worked. Siemens’ G2 generation of offshore turbines incorporated an enhanced version of the shield that, together with further improvements based on operational experience at Vindeby, maintained excellent working conditions for service personnel. Meanwhile, steep technological development has continued. What was the G2 platform is now purely an onshore platform. In offshore, there are ever-larger machines in operation, such as the Offshore Geared turbines in the 4 MW class and the Offshore Direct Drive turbines in the 6 to 8 MW class.

At a glance• Upwind turbine

• Three-bladed• Geared

• Asynchronous generator• Stall pitch

• Direct connection to the grid

At a glance• Upwind turbine• Three-bladed• Geared• Asynchronous generator• Pitch regulated• AC-DC-AC connection

to the grid

At a glance• Upwind turbine

• Three-bladed• Geared

• Asynchronous generator• COMBISTALL® pitch

• Direct connection to the grid

1995

11 turbinesTotal number of Siemens turbines installed offshore

G2 platform (now the Onshore Geared platform)

31 turbines

2000

Transforming wind into an asset | Turbine technology Turbine technology | Transforming wind into an asset

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Performance and profitabilityIn the ongoing search for cost-effective solutions, the late 2000s saw Siemens‘ resourceful engineers adapt direct drive technology from another branch of renewable energy: hydroelectricity. Direct drive dispenses with the gearbox to reduce complexity, leverage the benefits of simplicity, and boost efficiency.

Gearless efficiencyReplacing the gearbox, the coupling, and the high-speed generator with a low-speed generator eliminates two-thirds of the conventional geared drive train arrangement. As a result, Siemens direct drive turbines comprise fewer rotating and wear-prone parts than comparable geared models. Most importantly, no rotating parts in a direct drive turbine are operated faster than the rotor, whereas geared turbines operate at faster speeds, which can eventually lead to wearing out of the drivetrain components.

Simplicity and accessibility Siemens direct drive also benefits from permanent magnet excitation of the generator, which is regarded as the simplest and most efficient generator design. The simplicity reduces the weight of the turbine and gives service technicians more space inside the nacelle, making key components more easily accessible.

Future proven Siemens direct drive technology is the culmination of a holistic philosophy that balances design, material choice, processes, manufacture, assembly, and installation – all in order to maximize reliability. Siemens has been validating the technology since 2008, with a combination of field operation and dedicated laboratory testing. In 2009, the first Siemens Onshore Direct Drive turbines went successfully into operation. They were followed in 2011 by the first version of the Offshore Direct Drive platform.

2004. The Offshore Geared platform In 2004, Siemens launched the Offshore Geared platform with the introduction of the SWT-3.6-107, the first offshore wind turbine developed specifically for offshore energy production. All turbines based on the Offshore Geared platform benefit from the separation of mechanical components from the nacelle canopy, an innovation that offers enhanced protection against the offshore environment. It is just one of the features that have helped make the Offshore Geared platform the world’s most commercially successful wind turbine platform.

The first dedicated offshore turbine

The future of offshore wind power technology: direct drive

The evolution of a revolution In 2007, the best-selling SWT-3.6-107 was replaced by the SWT-3.6-120, which generated more power thanks to a larger rotor. In 2014, the launch of the 4-megawatt SWT-4.0-130 marked the culmination of a steady process of innovation and refinement of geared wind turbine technology. The strengths of the SWT-4.0-130 were confirmed when investors approved its selection for the 600 MW Gemini wind power plant in the North Sea, the largest-ever project-financed offshore wind power project to that date.

At a glance• Upwind turbine

• Three-bladed• IntegralBlade® technology

• Geared• Asynchronous generator

• Pitch regulated• AC-DC-AC connection

to the grid

Total number of Siemens turbines installed offshore

The Offshore Geared platform benefits from state-of-the-art IntegralBlade® technology that eliminates glue joints to deliver blades with the optimum balance of size, quality, strength, and reliability – without compromising the turbine’s structural load.

Offshore Geared platform

2001 2005 2010

45 turbines 117 turbines 500 turbines

Transforming wind into an asset | Turbine technology Turbine technology | Transforming wind into an asset

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2011. Introducing the Offshore Direct Drive platformTrue to Siemens’ ongoing cycle philosophy, the wind turbines in the Offshore Direct Drive platform incorporate the aggregate offshore know-how of the last quarter-century. Designed to IEC I requirements, direct drive turbines can potentially be deployed in any known offshore location. Key technologies were transferred from the tried-and-tested Onshore Direct Drive and Offshore Geared platforms and the structural capacity of all the components was verified by full-scale testing. The first Offshore Direct Drive turbine carries a rating of 6 megawatts.

2015. The Offshore Direct Drive platform, version 2 When Siemens engineers set about optimizing the Offshore Direct Drive platform, new magnet technology allowed an incremental upgrade of the electrical system allowed for increasing the generator rating by 17 percent. This led to the SWT-7.0-154, an upgraded version of the Offshore Direct Drive wind turbine that retains the basic structure, and all the advantages, of its 6-megawatt predecessor, but still generates up to 10 percent more annual energy production.

A breed apart: the Siemens Offshore Direct Drive platform

The leanest machineWeight was a core factor in the Offshore Direct Drive platform design from the very start. A low turbine weight delivers significant savings on substructure, shipping, and installation – and raises returns on investment.

Like the first offshore turbines installed by the Siemens team back in 1991, the Offshore Direct Drive platform is tailored specifically to offshore applications. Every exposed surface and system features offshore-grade corrosion protection, like the enclosed nacelle, which is fitted with internal climate control.

2016. The Offshore Direct Drive platform, version 3In 2016 we introduced the latest upgrade to the Offshore Direct Drive platform: the SWT-8.0-154. This was made possible through the introduction of new magnet technology with an even higher grade than introduced in the SWT-7.0-154. This enables a rated power increase of more than 14 percent from 7 MW to 8 MW and allows for up to 10 percent higher annual energy production.

At a glance• Upwind turbine

• Three-bladed• IntegralBlade® technology

• Gearless • Synchronous direct

drive generator• Pitch regulated

• AC-DC-AC connection to the grid

Total number of Siemens turbines installed offshore

2011 2015

655 turbines more than 1,700 turbines

Offshore Direct Drive platform

Transforming wind into an asset | Turbine technology Turbine technology | Transforming wind into an asset

2016

more than 2,100 turbines

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Powered by partnershipAs a pioneer and thought leader in the offshore industry, Siemens has accumulated unrivaled experience in adapting to the challenges that may arise when implementing rapidly advancing technologies.

As Siemens has strived to reduce the levelized cost of electricity, however, one thing has never changed: the company’s commitment to its partners. In addition to safety, your return on investment is Siemens’ first priority. With a combination of state-of-the-art turbine technology, ever-higher quality standards, innovative service concepts, continuous testing, and ongoing research, Siemens is committed to consistently delivering on its promises.

You can rely on the support of Siemens teams throughout the entire lifetime of your investment. Siemens employees constantly pursue innovation and improve on proven products, ensure reliability, and tailor an extensive service portfolio to your specific needs.

With thousands of turbines installed offshore, and a total capacity of more than 7.3 GW (as of 2016), Siemens has a vested interest in maintaining sustainable partnerships. You can rest assured that you will receive all the professional support required to maximize the security of your wind power investment over the long term.

Committed to robust offshore returns

Transforming wind into an asset | Investment robustness

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Published by Siemens AG 2016

Wind Power and Renewables Division Beim Strohhause 17-31 20097 Hamburg, Germany siemens.com/wind

For more information, please contact our Customer Support Center. Phone: +49 180 524 70 00 Fax: +49 180 524 24 71 (Charges depending on provider) Email: support.energy@siemens.com

Article-No. WPOF-B10018-00-7600 RS1501325BR0916

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Subject to changes and errors.

The information given in this document only contains general descriptions and/or performance features which may not always specifically reflect those described, or which may undergo modification in the course of further development of the products. The requested performance features are binding only when they are expressly agreed upon in the concluded contract.