Lobitos Solar Energy (PV)
Feasibility Study Technical Summary
Mark Hazelton
MSc. Renewable Energy (Newcastle University UK)
EcoSwell
2015
1. Introduction
1.1. Project background
1.2. Aims and objective
2. Structure of report
3. Solar energy development
3.1. Worldwide deployment trends
3.2. Solar PV in Peru
3.2.1. Overview of energy policy
3.2.2. Rural Electrification
4. How solar energy works
4.1. Solar cells
4.2. Solar panels and arrays
4.3. Current and Voltage of electrical systems
4.4. Standard operating conditions and panel specifications
4.5. Solar Irradiance
4.6. Batteries and Charge controllers
4.6.1. Types of battery
4.6.2. Charging and charge controllers
4.7. Inverters
4.8. Configurations of Solar installations
4.8.1. Stand-alone systems
4.8.2. Grid-tie
4.8.3. Grid-tie with power backup
4.8.4. Grid fall back
5. Stakeholder Analysis
5.1. Government structure
5.2. Energy
6. Assessment of applications
6.1. Introduction to the approach
6.2. Outline design methodology
6.3. Application scoping sheets of each application considered
6.3.1. Fishermen- Vessel recovery winch
6.3.2. Fishermen- Jib crane/winch
6.3.3. Fishermen- Lighting of fish quay
6.3.4. Fishermen- Pumping water for use in water tower
6.3.5. Residents/small businesses- Use of solar to offset electricity bills
6.3.6. Municipality- Lighting of football court
6.3.7. School- Use of solar to offset bills for the schools/for education
6.3.8. Municipality- Desalination of water to use in gardens/parks
6.4. Applications not considered
6.5. Discussion
6.6. Recommendation for application to take forward to detailed design
APPENDICES
A. Applications not carried forward
1. Introduction
1.1.Project background Lobitos is a small town on the north coast of Peru with a population of approximately 1,200
permanent inhabitants. It was formerly an affluent English port and oil extraction facility from
1903-1968 . Following military takeover of the government in 1968, the Peruvian government 1
nationalised oil extraction operations in addition to developing the area as a training base. The
area was a strategic position due to the proximity to Ecuador (there was an active dispute over the
area in 1990) and in order to protect oil interests. In recent years following de-escalation in
tensions between Peru and Ecuador the military presence in the area has been scaled back with
Lobitos become an increasingly popular tourist destination.
The Central Government is keen to attract developers
to fulfil Lobitos’ potential as a tourist resort. There are
a number of buildings that are unoccupied but in the
possession of the Peruvian army that are available to
rent that could be turned into hostels. There has also
been numerous new structures custom built to
accommodate tourists mainly along the beach front . 2
Ecoswell are the non-governmental organisation
facilitating this project. The organisation is a
collaboration between 5 Peruvian school friends with
a range of skills from social research, environmental
engineering to graphic design and sales. They have
formed with the aim of promoting sustainable
development in Lobitos through bringing in expert
teams to design and bid for funding to enable projects
that benefit the local community and economy. Tourism developments in nearby towns have been
environmentally and socially disastrous, something that Ecoswell hope that their actions will
avoid.
Ecoswell have completed a baseline social assessment in Autumn 2013 in order to assess the
primary needs of the community and test the feasibility of Ecoswells mission statement . 3
1.2.Aims and objective The aims and objectives of this project have been developed in partnership with Ecoswell and field
data capture has been completed in partnership with them. This overall aim of this project is to
1 https://surfinglobitos.wordpress.com/about/context/
2 http://surfinglobitos.wordpress.com/about/context/
3 http://www.ecoswell.org/home.html
gather relevant information and analysis in order to scope the potential for solar electricity
applications in Lobitos. Detailed design and financial analysis will then be developed for the most
promising application to sufficient detail to underpin an application for funding. Specific objectives
are:
1. Investigate current power supply arrangements, consumer usage, perceptions and issues
over power supply;
2. Assess the ability of current electricity services to complement integration of micro
renewable energy sources;
3. Establish the feasibility of using solar energy as either a supplementary source to
complement existing power systems or as a sole source for a variety of potential
applications;
4. Develop one potential application in detail to a level appropriate for a funding application.
The fieldwork and research required to achieve each of these objectives is described in greater
detail below.
Objective 1: Investigate current power supply arrangements, consumer usage, perceptions and
issues over power supply. Assess the ability of current electricity services to complement
integration of micro renewable energy sources.
● Review the EcoSwell social assessment
● Complete visual surveys of infrastructure
● Interview stakeholders from power generation and distribution companies to understand
the systems that are in place and any future investment plans for infrastructure in Lobitos
● Interview consumers to find out what appliances they have, their usage and expectations
of power.
● Collate, summarise and present evidence base
Objective 2: Establish the feasibility of using solar energy for a variety of potential applications in
Lobitos:
● Describe components that make up a solar PV system and considerations required in
design of such systems
● Using primary and secondary evidence, explore through factsheets the feasibility of
different solar electricity applications. These should include:
o Descriptions of the applications
o Stakeholders who would benefit from the application
o Findings from the fieldwork and interviews
o Any equivalent case studies and literature
o Analysis of the application using the Strengths, Weaknesses, Opportunities and
Threats (SWAT) assessment model
Objective 3: Develop one potential application in detail to a level appropriate for a funding
application
● Provided a detailed description of an optimised design
● Research and cost for appropriate equipment
● Complete financial analysis to calculate payback period on application
● Make the case for implementation of the application
● Provide maintenance and operation guidelines to allow Ecoswell and beneficiaries of the
application to understand maintenance requirements and the operating principals of
potential equipment
Fieldwork will be carried out over 2 weeks based in Lobitos in Spring 2014.
2. Structure of report The report has been structure with the following main sections:
3) Solar energy development: to give a background to the global development of solar
energy in recent years.
4) Solar energy theory: detailing the operation and factors in designing solar energy systems
5) Stakeholder engagement: detailing relevant overarching issues from the stakeholder
engagement that was completed on site.
6) Assessment of applications: detailing and appraising the shortlist of applications that
were defined from stakeholder engagement including outline designs of solar systems to
meet each requirement.
3. Solar energy development
3.1.Worldwide deployment trends The solar PV sector has seen large scale growth in installed capacity globally since the early 1990s
with a particularly strong growth since 2008. Figure 1 demonstrates this growth from a grid tied
installation perspective. This large scale growth has come about as a result of market mechanisms
being introduced to increase deployment in line with decarbonisation objectives, countries like
China investing heavily in both manufacturing and utilisation of solar PV as well as increased
efficiency and reliability of panels and components. (IEA, 2013) . Installed capacities of off grid 4
systems are much smaller approximately 2-4GW.
4
http://www.iea-pvps.org/fileadmin/dam/public/report/statistics/PVPS_report_-_A_Snapshot_of_
Global_PV_-_1992-2013_-_final_3.pdf
Figure 1: Worldwide installed capacity of grid connected solar PV (dark blue signifies capacity in the International Energy Agency’s Photovoltaic Power Systems Programme and light blue other countries)
5
Figure 2 demonstrates the falling cost of solar PV units that has been a factor in the wide scale
growth in installed capacity of solar PV modules. The price drop that this Figure demonstrates can
be attributed to advanced production techniques as well as oversupply of solar PV units to the
market as demonstrated in Figure 3.
Rüther (2011) identified the selling points of small scale solar PV in areas where grid connection is 6
unavailable, costly or near to capacity as:
● Reduced strain on grid infrastructure at peak load times through self-consumption of
locally generated electricity.
● Saving on expansion and reinforcement of grid systems where solar can be used as
primary energy source.
● The energy generated by PV modules in the daytime could save on other grid connected
generation capacity.
5 IBID
6 Rüther R, Roberto Zilles (2011), Making the case for grid-connected photovoltaics in Brazil,
Energy Policy, Volume 39, Issue 3, March 2011, Pages 1027-1030, ISSN 0301-4215.
Keywords: Solar energy; Grid-connected photovoltaics; Value of photovoltaic (PV) electricity
Figure 2: Indicative prices for small scale systems in two indicative IEA PVPS countries 7
Figure 3: MW of solar PV units produced against installations 8
7
http://www.iea-pvps.org/fileadmin/dam/public/report/statistics/PVPS_report_-_A_Snapshot_of_
Global_PV_-_1992-2013_-_final_3.pdf
8
http://www.iea-pvps.org/fileadmin/dam/public/report/statistics/PVPS_report_-_A_Snapshot_of_
Global_PV_-_1992-2013_-_final_3.pdf
3.2.Solar PV in Peru
Overview of energy policy
Peru has seen high rates of economic growth driven by increased energy intensive mining of
copper, silver, lead and zinc . This has led to the country's energy demand being the 4th highest in 9
Latin America.
52% of Peru’s electricity is generated from renewable with large scale hydro making up the
majority of this capacity (43% of the total). Other technologies that are utilised include biomass
and waste, solar and small hydro. Natural gas, oil and diesel account for the remaining capacity . 10
In order to support the development of renewable technologies (excluding large scale hydro), the
Ministry for Energy and Mines (MEM) has introduces and number of incentives such as technology
specific auctions, giving fixed prices for 20 years, and incentives to support investment in
infrastructure to support renewable energy development. However these incentives are aimed at
utility scale developments with capacities of MWs rather that small scale feed in generation.
The renewable energy auctions have been carried out since 2009 and have succeeded in funding
approximately 2,200GWh/year of renewable energy from small hydro, solar PV, wind and Biomass
. These auctions target utility scale generation rather than the small micro scale generation 11
under consideration in this project
Overall electricity prices are directly subsidised by the Peruvian government but anecdotally still 12
are the single greatest household expenditure for customers in communities such as Lobitos . 13
New connections can also be costly with electricity distribution companies focussed on urban
centres (less than 100 homes), with no obligations to meet demands over 100 meters from the
existing network.
Rural Electrification From 2007-2015 the Peruvian government implemented a rural electrification programme with a
strong emphasis on solar PV. The programme was funded by the World Bank and targeted the
connection of 160,000 rural properties where grid connections were not feasible . Due to 14
significant cost increases on estimates, the project fell 34% short of meeting its target but has
demonstrated that the potential for wide scale deployment of solar PV for powering off grid
9 http://www.kpmg.com/PE/es/IssuesAndInsights/ArticlesPublications/Documents/Country-Mining-Guide-Peru.pdf 10 http://export.gov/reee/eg_main_074747.asp
11 http://www.irena.org/DocumentDownloads/Publications/IRENA_Renewable_energy_auctions_in_developing_countries.pdf 12 http://www.ifc.org/wps/wcm/connect/78f59b00493a76e18cc0ac849537832d/SEF-Market+Assessment+Peru-Final+Report.pdf?MOD=AJPERES 13 Need a link to appendix interviews on the price of electricity 14 http://www-wds.worldbank.org/external/default/WDSContentServer/WDSP/IB/2014/01/27/000442464_20140127095748/Rendered/PDF/ICR23580P090110C0disclosed010230140.pdf
applications. The project has also had the benefit of raising awareness and technical capacity in
Peru . 15
There was limited take-up of the project in the Talara Province and a nil response from the Lobitos
local government to the scheme . This was due to the good levels of grid availability in the area 16
but also the belief of those residents who do not have access to grid supplied electricity that
inclusion in the scheme would harm future chances to access grid electricity.
4. How solar energy works
4.1.Solar cells PV panels generate electric current from photons of energy emitted by the sun and by utilising the properties of semiconductor materials, most commonly silicon. Materials have two energy bands that describe the energy state of electrons in a material and associated properties. These are the conduction band and a valence band. Electrons in the valence band do not have sufficient energy to break the attraction to their associated protons in the atom. Electrons in the conduction band have sufficient energy to break these bonds and therefore can move to other atoms in the material. The energy taken to move between these two bands is termed the bandgap which varies with each material. When an electron moves from the valence band into the conduction band breaking the bond with its atom, an associated hole is produced which other electrons can move into. This allows the passage of electrons through the material forming and electric current. Conductive materials generally have many electrons in the conduction band meaning that electrons can move freely through the material. Insulators and semi-conductors generally have a full valence band and no electrons in the conduction band. This means that no electrons can pass through the material. In semi-conductor materials the bandgap is sufficiently small to allow the elevation of electrons to the conduction band and associated holes to be produced by the addition of heat or light. This then allows electric current to pass through the material. When a semiconductor material has an electron hole pair, the electron is negatively charged and the hole is positively charged. In order to increase the electrical carrying capacity of the semi-conductor, the two substances are introduced to different parts of the solar cell. To provide more electrons, one side of the silicon cell is doped with prosperous forming n-type material. Boron is added to the other side of the cell to provide more holes to form p-type material. When the two materials are joined the extra electrons from the n-type material move to the p-type material and vice versa until the negative charge created by the electrons in the p-type material and corresponding positive charge in the n-type material form a barrier to other electrons crossing between the two. This is termed the p-n boundary and is described in Figure 4. The p-n boundary is essential to allow the electron hole pairs that are created by the introduction of light to be separated long enough to allow electrons to through an external circuit.
15
https://books.google.co.uk/books?id=709IhPbvf00C&pg=PA156&lpg=PA156&dq=FOSE+cross+sub
sidy&source=bl&ots=XWcjJACQGe&sig=yyYBdNTjinY4z1RiIRhZuVrU6dA&hl=en&sa=X&ei=Xe8rVaje
DMLZarv3gYgG&ved=0CC8Q6AEwAw#v=onepage&q=FOSE%20cross%20subsidy&f=false
16 Appendix the Mem guy interview
4.2.Solar panels and arrays To provide sufficient electricity at an appropriate voltage to allow the effective supply to power a
variety or multiple loads, panels are usually installed in conjunction forming an array. Connecting
multiple panels in an array will always increase the system wattage however the layout of
connection will change the characteristics of the system and is an important consideration in
designing a solar system.
Connecting solar panels in series as shown in Figure 5 generates electricity at a higher voltage
whereas connecting panels in parallel as in Figure 5 generates the same voltage as a single panel
but increases the current of the system. For example if you connect three 12 volt 12 watt panels in
series you would get a 36V 36W array with 1amp current. Connection in parallel this would
produce 12V and 36W with a 3amp current.
Figure 5: Series and parallel connection diagrams
4.3.Current and Voltage of electrical systems Alternating Current (AC) and Direct Current (DC) are the two formats of current that can be
supplied. AC is generally the format used in grid systems in order to reduce losses over long
distances. DC is the format supplied by both solar panels and batteries. Converting DC into AC
causes losses of power and therefore should be considered carefully when designing solar
systems, especially small installations. Differing loads are designed to work on either AC or DC and
many appliances are available as either DC or AC compatible.
The relationship between voltage and current is described as:
ower oltage urrentP = V * C atts olts mps W = V * A
This means that both the current and the voltage contribute to the overall power. If a system is
running from a 12V battery and is powering a 60W light bulb a current of 5 amps would be
required (60/12=5). Similarly if the same lightbulb was running from a grid supply at 240V then a
0.25amp current would be required (60/240=0.25).
The relationship between power and resistance can be calculated as:
ower esistanceP = Current2 * R
atts mps hms W = A 2 *O
This explains why grid systems run at a high voltage as the lower the current the lower the
resistance and therefore fewer losses that would occur when transporting electricity through
transmission lines. Using the same example above, a 60W light bulb running from a 12V source
would require 5amps to run. This would result in a resistance of 0.417ohms (52/60=0.417)
whereas the higher voltage setup would produce 0.001ohms (0.252/60=0.001). Although there
are advantages to running at very high voltages most appliances, batteries and controllers
designed to for use in solar systems run at either 12V or 24V . 17
4.4.Standard operating conditions and panel specifications Solar panels offer varying levels of power dependant on conditions. As such the rated wattage of a solar panel is defined under a series of Standard Operating Conditions. These criteria are:
1. Temperature of the cell – 25°C. The temperature of the solar cell itself, not the temperature of the surrounding.
2. Solar Irradiance – 1000 Watts per square meter. This number refers to the amount of light energy falling on a given area at a given time.
3. Mass of the air – 1.5. This term is misleading as it refers to the amount of light that has to pass through Earth’s atmosphere before it can hit Earth’s surface, and has to do mostly with the angle of the sun relative to a reference point on the earth.
The rated wattage that is supplied is termed the peak Watts (pW) that would be supplied under the conditions listed above. Oversizing of the system is essential to allow for the variable conditions and component inefficiencies. For example, the solar handbook (2015) notes that if
18
an inverter is utilised the system would need to be oversized by 10% and for 5% if batteries are used. Other data that is often supplied in panel specifications are open circuit voltage (Voc) and short circuit current (Isc). In addition maximum power point voltage and current (Vmp and Imp) are also generally advertised. Voc shows the operating voltage with an open circuit (i.e. no load) with Isc showing a complete short circuit (see Figure 6). These figures are important when sizing other components in the installation. For example:
● The Voc and Isc of the installation cannot exceed the stated input current and voltage of
the charge controller or PV-inverter. 19
● Isc is maximum amperage that could be generated by a panel. This number should inform
the wiring size and circuit protection like fuses. PV shop recommends that a charge
controller should be rated at 125% above the Isc. For example a 50A controller should
have a system Isc of no more than 40A (50/1.25 = 40A).
● The Vmp should not be higher than (but optimally close to) the maximum battery voltage
. 20
17 82+83+24
18 Solar handbook
19 http://pvshop.eu/offgrid 20 http://www.operatingtech.com/lib/pdf/A%20Guide%20to%20battery%20Charging.pdf
Figure 6: Relationship between current and voltage and the maximum power point
4.5.Solar Irradiance Solar irradiance describes the amount of solar energy that can be gathered by a panel at a certain
location. The amount of solar irradiance is affected by:
● the latitude of the location; both through the amount of sunlight that is experienced in the
location and the amount of atmosphere that the photons of light have to travel through
● the local meteorological conditions; general levels of cloud cover and precipitation
● the specifics of the site; shading through any relief, vegetation or buildings that could
block out more of the sun at certain parts of the day or year.
Lobitos is situated at -4.460 latitude and -81.279 longitude . The National Renewable Energy 21
Laboratory’s (NERL) Climatological Solar Radiation (CSR) Model estimates that the amount of 22
solar energy intensity in the area around Lobitos 5kWh/m2. The CSR model uses a 40 km
resolution and includes parameters on cloud cover, atmospheric water vapor and trace gases, and
the amount of aerosols in the atmosphere.
Table 1: Average monthly solar energy intensity in Wh/m2
Jan Feb Mar Apr May Jun
4111 3684 4445 4731 5243 5505
Jul Aug Sep Oct Nov Dec
21
http://www.distancesfrom.com/Lobitos-latitude-longitude-Lobitos-latitude-Lobitos-longitude/LatL
ongHistory/3513492.aspx?IsHistory=1&LocationID=3513492
22
http://en.openei.org/datasets/dataset/solar-monthly-and-annual-average-direct-normal-dni-glob
al-horizontal-ghi-latitude-tilt-and-2
Figure 7: Solar irradiance in Latin America
Table 1 shows the variation in intensity is from 3684 to 5844 Wh/m2 which would have to be taken
into account in the design of a solar system with the lower power intensity used to size the system
if there is no seasonal variation in load.
The irradiance value requires combination with a time value to create Wh/m2/day or peak sun
hours. This is roughly 5.5 for the Lobitos area . 23
4.6.Batteries and Charge controllers A key component of stand-alone solar PV system is the battery bank. This stores excess energy and allows the delivery of power to loads in a consistent and balanced way. The size of the battery bank for any application has the potential to dramatically increase cost and certain loads are not suited to being serviced by batteries (i.e. large intense loads that require a lot of power over a short period of time).
Types of battery
Batteries operate by utilising elements with large differences in affinity submerged in an electrolyte. Affinity is the amount of energy that is release when an electron is added to an element to form a negative ion with differences in affinity being created by electrons moving from
23 http://www.oynot.com/solar-insolation-map.html
one atom to another to be at a lower energy level. An electrolyte is a liquid with positive and negatively charge ions that can transfer a current. A material with electrons at a high energy state forms the negative terminal of the battery, the anode. The cathode forms the positive terminal of the battery and is made from material with electrons at a low energy state (see Figure 8). When the circuit is connected the electrons from the anode transfer around the circuit to the cathode leaving positively charged ions in the anode material. These ions then transfer to the cathode material through the electrolyte forming a current. When recharging a battery the process is reversed with electrons effectively forced back into the anode material. The majority of large scale batteries use lead acid as the electrolyte and the material of the anode and cathode varying depending on the voltage requirements of the battery. Conventional flooded lead acid batteries contain aqueous lead acid which can spill if the battery casing is damaged. As a byproduct of the electrolysis reaction that takes place in a lead acid battery, hydrogen gas is produced. This has possess a potential safety hazard if the batteries are not situated in a well-ventilated location. This also leads to the requirement of battery maintenance to top up the levels of electrolyte in the cell. There are two types of battery suitable for use in conjunction with solar systems. These are Gelled Electrolyte Sealed Lead Acid (GEL) batteries and Sealed Absorbed Glass Mat (AGM) type batteries. Both have different characteristics and which can be utilised to power different load profiles. Sealed Absorbed Glass Mat (AGM) AMG batteries are a version of lead acid batteries where the acid is absorbed in a fine fiberglass matt between the anode and cathode. This means that the battery is spill proof and maintenance
free. The internal resistance of AGM batteries is low with the result that relatively high currents can be delivered over a shorter period of time that gel batteries. Even with these characteristics AGM cells can still offer a depth of discharge of around 80% The negatives are slightly lower specific energy and higher manufacturing costs that the conventional flooded lead acid units. AGM cells are best suited to cell sizes from 30 to 100Ah. Advantages of AGM cells are:
● Spill-proof as the acid is absorbed in a fiberglass matt ● Low internal resistance and therefore can power more challenging loads ● Up to 5 times faster charge than with conventional flooded lead acid batteries with good
depth of discharge properties ● Electrolyte retention is good meaning less hydrogen is produced through gassing
Limitations are: ● Higher manufacturing cost than conventional flooded lead acid batteries but cheaper than
gel ● Sensitive to overcharging (gel has tighter tolerances than AGM) ● Capacity gradually declines over the life of the battery
Gel Batteries Gel batteries work on exactly the same principle as lead acid batteries by the electrolyte is suspended in a paste induced by adding silica. Gel batteries have strong performance with repetitive cycling and age with the original capacity of the cell being maintained before steeply dropping off with age. The gelled electrolyte also reduces the amount of hydrogen emitted by the cell during discharge meaning low maintenance and increased safety. The internal resistance of gel batteries is greater than that of AGM cells meaning that gel batteries are more suited to a longer constant discharge and recharge which is suitable for many applications e.g. lighting. Advantages of Gel cells are:
● Spill-proof as the acid electrolyte is absorbed in gel form ● The performance over the lifetime of the battery is much better than conventional lead
acid and AGM cells
● Electrolyte retention is good meaning less hydrogen is produced and less maintenance is
required
Limitations are: ● Higher manufacturing cost than conventional flooded lead acid batteries and AGM cells ● Higher internal resistance than AGM batteries and therefore requires discharge and
recharge to be performed over a longer time
Charging and charge controllers
The amount of energy that a battery can store is rated in Amp hours (Ah) and refers the
theoretical chemical energy inside a battery that can be converted to electricity however this
rating varies with the time taken to discharge the battery. The C rating describes the amp hour
output at a constant current over a period of discharge. For example, if a 5Ah battery is discharged
over 1 hour, the battery would output 5A for an hour. An hour discharge is termed C1, a half hour
discharge 2C and a two hour discharge 0.5C. Lead Acid batteries provide more Ah per discharge
when run at a lower C-rating with advertised battery ratings supplied at 0.05C (20 hour discharge).
The life cycle of a battery reduces with the depth of discharge of each discharge cycle. As an
example an 84Ah load can be serviced by the 8G24 12V 84Ah battery . At 100% discharge, the 24
battery will last for 500 cycles but 1100 cycles if 50% discharged. Assuming 84Ahs are used at
100% discharge every day the battery would last 1.4 years whereas at 50% depth of discharge the
same battery would last 3.0 years although 2 batteries would be required to power the load. The
cost of battery units and depth of discharge levels are important when factors to consider when
assessing a stand-alone PV installation. Appropriate levels of depth of discharge will be
investigated and optimized in the detailed design using equipment data sheets supplied by the
manufacturer.
Charge controllers are required to manage the division of electricity between the battery bank and
the load. The charge controller can also manage charging and draw down of electricity from an
array of batteries equalizing the inputs and output to ensure not battery is under unnecessary
stress. Maximum power point trackers are available with some charge controllers which ensures
the efficient generation of electricity from the panel array by modifying the voltage of the circuit
to ensure that the panel is operating at the maximum power point (see section 4.3). Ground fault
protection to protect the battery bank and panel array in the event of a short circuit is also often
included in in the charge controller. Selection of a charge controller should depend on the system
voltage, the current of the system and the maximum current of the load.
4.7.Inverters An inverter is a device that converts DC current to AC as well as modifying the voltage on a circuit. Inverters are often used to power loads that have been designed to run on grid specified electricity (see section 5.2 for the grid design in Lobitos) with solar PV systems that generally work at lower voltage DC currents. Grid tie inverters work in tandem with the panel installation, electrical loads and the utility grid. Power is sent to loads preferentially with any excess being exported to the grid through a meter. Grid tie inverters incorporate harmonising features to ensure electricity is exported in phase with the grid and also safety features to cease exportation during utility power cuts.
24 http://www.mrsolar.com/content/pdf/MKBattery/8G24.pdf
There are two ways that inverters modify DC current to AC: modified sine wave signals and pure sine wave signals. The difference between the two approaches are that modified sine wave inverters produce a block of current with some time spent at zero current as demonstrated in Figure 9. Pure sine wave inverters produce a smooth output which is the same as utility grid electricity. Modified sine wave inverters are generally cheaper but some electrical appliances do not operate with modified sine wave inverters and others produce a humming noise. This is generally the case when an appliance uses the zero crossing point of the AC current to measure time or a where a microprocessor in an appliance is used causing interference (e.g. electric blankets and coffee makers) .
25
4.8.Configurations of Solar installations There are four different operational modes for solar PV systems. These are:
1. Stand-alone systems
2. Grid tie systems
3. Grid tie power backup systems
4. Grid fall back systems
Each mode of operation is suitable for different applications depending on factors such as: the size
of the load, the criticality of the loads operation, availability of grid and the grid operators policy
for accepting excess locally generated electricity onto the grid.
Stand-alone systems Stand-alone PV systems are suitable for applications where a source of grid power is not readily
available or when it is not cost effective to extend the grid to a load. The PV system is designed to
be the sole source of power for a load. If the load is required to be powered on demand or
throughout the night then a battery bank is required to enable the correct wattage to be supplied
regardless of the atmospheric conditions and irradiance landing on the panels. The loads that are
powered by these systems are generally comparatively small, around a kilowatt, as large loads
would require an extensive array of photovoltaic panels and a large battery bank.
The components of this system setup include: panels, a solar controller, a battery bank and could
also include an AC inverter depending on the load.
Grid-tie In grid-tie systems, solar and grid electricity are designed to work together to supply cheaper
power when it is available from the PV system and export excess to the grid. When there is
insufficient power supplied by the PV system, the load can be powered using grid power. In many
countries there is often a feed-in-tariff incentive where the grid operator will pay for power to be
exported to the grid. This is not currently available in Peru.
This type of system includes: panels, a grid tie inverter, a grid tie meter and a distribution panel.
25 http://www.xantrex.com/documents/tech-doctor/universal/tech1-universal.pdf
The control panel is use as a hub for circuit breakers and safety systems similar to the control
panel used in most domestic electricity systems. This is due required due to the high voltage of
electricity that is supplied to get it to grid voltage.
Grid-tie with power backup The grid tie with power backup solution is very similar to the standard grid tie setup but also incorporates a bank of batteries. These systems are used for applications where grid power is unreliable or where continuous supply of electricity to the load is essential. The batteries are charge using electricity supplied by the panels in preference to exporting to the grid. Once the battery bank is fully charged excess power is then exported to the grid and would be eligible for a feed-in-tariff payment if applicable. The setup of the system is similar to the grid-tie system but with the addition of a battery bank and a charge controller upstream of the inverter. If power is being drawn down from the batteries, this will need to pass through the inverter to allow conversion to AC and stepping up to the appropriate voltage to power the load.
Grid fall back
The grid fall back system is suitable for applications where no feed-in-tariff incentive system is in place, where users are looking to reduce bills and/or reduce the impact on the environment. The system works by incorporating a design setup similar to a stand-alone system but maintains a link to the grid. The system uses the solar power as a preference but as the batteries run flat will switch back to the grid to supply power allowing the batteries to recharge. The components of the system are similar to the stand-alone system but there is a difference in the two types of power source. Grid electricity is usually supplied at high voltage and low current in AC. Batteries on the other hand work best at low voltages and supply in DC. Accordingly, the load and system has to be designed to work with one or the other formats of electricity supply. Generally in this case grid power run through an inverter to convert it to DC and lower voltage as the batteries will generally be the main source of power and, especially for small systems (under a kilowatt), the efficiency losses in converting low voltage DC to high voltage AC would be too great.
5. Stakeholder Analysis Stakeholder analysis was undertaken based on the interviews that were conducted during
fieldwork in Peru and forms the primary evidence for this study.
Information taken has been used from each of these interviews has been utilised in the
application assessments and referenced accordingly. Sections 5.1 and 5.2 describe evidence on
government structure and electricity arrangements that are relevant across applications listed in
section 6.
5.1.Government structure There are 3 levels of government in Peru: Central, Regional and District municipality. The Peruvian
government has been implementing a process of decentralisation of responsibilities and funding
since 2002 . Table 2 outlines the differing responsibilities of each tier. 26
Central government manages overall policy direction and large scale projects and is therefore not
a particularly strong stakeholder in this study.
The Regional government in this area covers the whole of Piura region with a sub level covering
the Talara District within which Lobitos sits. This level is responsible for planning of regional
development, executing public investment projects, promoting economic activities, and managing
public property . 27
The District Municipalities are responsible for providing local services and infrastructure,
regulating building construction and granting businesses licenses. They are responsible of
construction and maintenance of roads, bridges, schools, health centres, irrigation projects, water
and sanitation, parks, markets, etc. The District Municipalities have relatively close ties to the
central government due to their main sources of funding for infrastructure works being through
the central CANON funding. The overlaps and relationship with regional government in practice
are not well established.
Sector National Regional Local Environment ✓ ✓ ✓ Industrial Policy ✓ ✓ Roads and telecoms ✓ ✓ Energy ✓ ✓ Local economic development
✓ ✓
Parks and recreation ✓ Water, sewage and sanitation
✓
Table 2: Areas of responsibility for all government tiers 28
National Government
No interviews were undertaken with the National Government however through interviews with
the fishermen it was established that the Ministry of Production (responsible for fisheries
management) had previously invested in solar lighting in Lobitos. This and other departments such
as the Department for Energy and Mining may provide a potential funding source if projects
overlap with their remit/policies.
26http://www.caf.com/media/3124/algovernmentscapacityandperformanceevidencefromPeruvian
municipalitiesdeFernandoArag%C3%B3nyCarlosCasas.pdf
27 planning regional development, executing public investment projects, promoting economic
activities, and managing public property
28http://www.cepal.org/ofilac/noticias/paginas/9/49309/Neyra_EN.pdf
Regional Government
Meetings were carried out with the Natural Resources and Environment Officer and Renewable
Energy Officer from the regional government. These departments have managed the delivery of
numerous projects including the central government’s Programme for Rural Electrification which
is funded by the World Bank (see section 3.2.2). The goals of this project are to supply power
through solar systems to properties where extension of the national grid is too expensive or
technically unfeasible. Eligible properties are supplied with Solar panels, batteries and all other
equipment free of charge. Nationally, approximately 500,000 properties are eligible with 10,000
located in Piura region (so far 2,000 systems have been supplied). These numbers were from the
first year of the 4 year scheme which represents a relatively strong take-up however there was a
nil response from Lobitos.
District municipality
Numerous interviews were undertaken with the District Municipality. It was established that they
have some capacity in engineering, infrastructure and environmental disciplines.
Selected recent and current projects include:
Programme to collect litter on Mon, Weds, Fri;
Tarmac road construction in last 3 months;
Improvements to the docks, provision of moorings;
Management and action on land invasions. There have been issues with
developers, land bankers (taking advantage of ownership through occupation) and
Illegal hostels developing too close to the sea and reducing access to the beach for
the locals.
They also recently funded drainage channels to handle extreme flows in storms.
There are three sources of income for the municipality : 29
Renta Aduana, which is a percentage of customs duties paid to the municipality;
FONCOMUN, the municipal compensation fund which provides funding to
municipalities based on a number of deprivation indicators;
Canon funding, administered by Ministry of Economics and Finance using a
mechanism called SNIP.
The first two sources pay for the overheads and revenue costs of the municipality. The Canon
funding is made up of levies charged on the oil companies and geographically linked to Lobitos so
there is a budget set aside for Lobitos to bid into.
29
http://www.google.co.uk/url?sa=t&rct=j&q=&esrc=s&frm=1&source=web&cd=2&ved=0CCQQFjA
B&url=http%3A%2F%2Fwww.inicam.org.pe%2F2006%2Fdescargar%2Fsubstitution%2520effect.do
c&ei=0BCJVazzG46R7Abp7YO4BQ&usg=AFQjCNE0rnDUN1f3PujEO5mYlVqIKh6Uzg&sig2=AqOt31y
x1vrWg8avE5_NUg
In order to affect this strategy the municipality aims to make Lobitos an attractive place to come
for hostel owners and customers. Due to the type of tourism the municipality want to attract
sustainability is high on the agenda with recycling, litter picking and waste management a key
part. They are also planning to make Lobitos green with trees and grass being planted in New
Lobitos and further when possible.
5.2.Energy Interviews were undertaken with a local electricity generation facility, EEPSA, and the regional
transmission system.
Generation
EEPSA are an electricity generation company, generating electricity to feed into the Peruvian
national grid. They are one of many privately owned electricity generation companies that operate
in Peru and are owned by the ENDESA who are a Spanish power company.
The Piedritas plant consists of 3 turbines fuelled by natural gas with a combined generation
capacity of 250MW. The parent company ENDESA operations in Peru include hydro-electric and
thermo-electric facilities (coal, gas and some diesel).
EEPSA have an active corporate responsibility scheme with projects including the construction of a
school in the nearby town of Piedritas. EEPSA also funded a grid connection programme for a poor
area on the outskirts of Talara and a pig farm through their corporate responsibility funds.
In order to fund corporate responsibility projects, clearance is needed from the parent company
(ENDESA) communications department. This is based in Lima but there is no scope to what EEPSA
would be willing to fund and confirmed that projects in Lobitos would be considered.
Transmission
ENOSA are 100% government owned and run but with the aim of making a profit. Regulation and
policy is defined by the Ministry of Energy and Mining. ENOSA control the purchase of electricity
from generators, balancing the lowest cost of energy with fluctuating demand, as well as
managing distribution, local connections, metering and billing of customers.
The ENOSA office in Talara manages the area from Tumbles in the North to Piura in the South
which includes Lobitos.
Electricity is supplied to Lobitos by an 8 km line from the main grid. This is currently mono-phase
however the growing demand for power from Lobitos means that ENOSA are currently scoping the
need for upgrading this area to tri-phase electricity.
When discussing the potential for local energy generated to alleviate some of the need for
upgrading the system, ENSOA did not believe this would be a viable option. There is potential to
feed solar generated electricity into the grid but ENOSA will only negotiate for generators with a
minimum capacity of 1MW. If the system were to supply MW into the grid ENOSA would pay for
the infrastructure to do so and negotiate a buying price and estimated power demand.
For smaller scale systems ENOSA presented two options for export to the grid:
1. The project is designed, financed and constructed by EcoSwell. The ownership, operation
and monetisation of the system would then be sold to ENOSA who will make profit from
the system.
2. Electrify areas that do not currently have electricity and when/if grid is extended to these
areas negotiations could take place to agree a price for electricity.
If the project were to disconnect a building or facility that was currently connected to the grid
there would be a very small charge. To reconnect them to the grid (for example if the solar system
failed) there would be a large reconnection charge.
The grid operates on 13.2Kv mid tension and 220v at low tension. The frequency is 60hz
6. Assessment of applications
6.1.Introduction to the approach Applications have been assessed through a series of factsheets outlining the issue and rough costs
of a potential solution using solar PV. These factsheets are to give a quick assessment of the
feasibility of a potential application with one solution being taken forward for detailed design and
financial analysis.
6.2.Outline design methodology For each application that was investigated in Lobitos, an outline appraisal of the suitability of the system, site and a rough design will be conducted to give a general idea of feasibility and how the application could work. This assessment will consider the following factors:
● Visual site survey ● Estimation of load ● Outline design of solar system ● Outline cost
The visual survey will include photographs and a description of the site for each application. Commentary on the shading and exposure of the site throughout the day will be commented on. A description of the grid availability will also be supplied for each site. The estimation of load will be completed using the template in figure 1. Where possible, real data will be supplied based on site investigations but where this is unavailable, the power requirements of new equipment will be used or the estimation of general power usage of appliances listed in the Solar Energy Handbook 2015.
30
The outline design will consider the following variables:
● Mode of operation ● Load assessment ● Battery bank required ● Panel array requirements ● System sizing including efficiencies
30 Estimation of load 32
Efficiencies will be accounted for in the calculations for each application. Fixed values will be used for panel array efficiencies (75%) and battery efficiencies (85%) . Panel array efficiencies account
31
for the fact that the panel will be generating power outside of standard operating conditions with temperature, irradiance and potential fouling of the panels all reducing theoretical output of the panels. Battery efficiencies take account of the fact that batteries cannot fully deliver 100% of power input back as power output. Variable efficiencies include inverter efficiencies, battery temperature compensation and shading efficiencies. Inverter efficiencies are defined by the manufacturer and account for the fact that inverters cannot transform 100% of input power to output power. The battery temperature compensation is applied to account for the variability in performance of the battery relative to average temperature and will be based on manufacturer defined data. Shading efficiencies will be applied to account for the potential loss of irradiance due to obstructions around the site. Other variables include the depth of discharge appropriate to a battery bank and the number of days of autonomy that batteries would have to supply the system for in the event of a power supply outage. These variables have been explained for each application.
6.3.Application scoping sheets of each application considered
6.3.1 Fishermen- Vessel recovery winch
Application title Winch for fishing vessel haul out
Stakeholder
group
Association Gremio de Pescadores Artesanales ARPA (Association of local fishermen)
Application description
There are approximately 61 vessels that use Lobitos as a home quay. Facilities include a production building that is largely disused, a concrete quay, moorings and area on the beach for storing vessels when they are brought onshore for maintenance. There are usually 7 vessels onshore at any time. Rope and timber sliders are used to drag the vessels ashore manually (Photograph 3), This is completed biennially per vessel. There are a variety of vessel sizes with the biggest vessel that uses the quay able to carry a capacity of 12 tonnes (see Photograph 1). The actual vessel weights that are required for calculations were not available. The ARPA previously had a bollard/runner system to aid in hauling boats up the beach but this has been abandoned after an accident when the rope snapped causing serious injuries. This incident has made the fishermen cautious about tools such as winches and pulleys however properly designed and maintained equipment could make this activity a lot safer and easier. The ARPA are not a cash rich organisation with a very modest turnover from subsidies paid by fishermen. This means that any application should require very low maintenance and running
31 Mayfield,Photovoltaic design and installation, pg 218
costs. The ARPA are able to apply for funding from a variety of sources including the Municipality and the Ministry of Production. This could support the initial capital costs of the project. The skills available in the ARPR are also minimal when it comes to non-fishing activity. This was demonstrated by the case study of the solar lighting project that was abandoned and removed (see application scoping sheet 6.3.3). This means that simple systems should be preferred and budget allocated for adequate training and maintenance plans.
Photograph 1: Example of the largest class of boat that docks in Lobitos
Photograph 2: Large vessel at mooring around the fish quay
Photograph 3: Example of current method of bringing vessels ashore
Photograph 4: Vessel on the beach and moorings in the background
Case studies
The Food and Agriculture Organization of the United Nations (FAO) report highlights that beach 32
clearways are appropriate for launching and recovering vessels of approximately 5 tonnes assuming vessels have the necessary modifications made to the hulls. This has the benefit of not requiring a concrete slipway structure to be built with associated geomorphology impacts and maintenance requirements. In Lobitos wooden skids are used to aid the manual recovery of
32 http://www.fao.org/docrep/013/i1883e/i1883e08.pdf
vessels up the beach and reduce friction on the sand. Any winch design would have to take into account the extra pulling power required to pull vessels up the variable gradient of the beach. Possible types of winch that are available include a small tractor, manual winch, electric winch or hydraulic winch (generally powered by diesel engine). The FAO report notes that for smaller artisanal fleets, a the hand operated 1 - 2-tonne winch is usually sufficient with the winch requiring concrete plinth at least 500 mm thick as an anchor. There are no readily available examples of solar winches available however a unit capable of pulling 4.5tonnes available at a power rating of 3.8kW at 12V .
33
Outline design
Visual site survey and mode of operation For a PV array of the size potentially required for this application, the production facility roof would be an appropriate mounting point. The only potential shading obstructions in the area are from the water tower situated to the north and an area of relief to the east however these are minimal. Due to the very large potential load, a hybrid PV and diesel generator system would be most suitable for this application however the cost of maintaining and fuelling a generator would be extra expenditure to the ARPA. A grid fall back system with an electric winch would also be appropriate however this would also lead to extra expenditure every time the winch was used as metered electricity would be used to part power the load. For these reasons a stand-alone solar system has been investigated. Load assessment vessel recovery winch To work out the power of the winch required the following equation will be used :
34
(s ) p = w + c
Where: ull on the hauling rope in tonnes p = p
weight of the vessel w =
tanθ (θ ngle of slope of the slipway) s = = a
coefficient of friction 0.25 c =
33 http://www.innovation-engineering.co.uk/LP8500_recovery_winch.htm
34
http://www.civil.iitm.ac.in/people/faculty/srgandhi/International%20%20Conferences/paper34.p
df
Using the largest gradient of the beach (15o) and an estimate of the unladen weight of the largest vessels that are brought ashore (8 tonnes) this would mean:
(tan15 .25) p = 8 + 0
≅4 tonnes p
Using the example winch which can pull 4.5tonnes at a power rating of 3.8kw at 12V this system
35
would need to run at a current of: I = v
W
I = 123800
316.6ampsI =
Taking the information on general haul out practices, the winch would be used to haul out a vessel approximately 31 times a year (61/2). It is also assumed that the haul out time would be 1 hour for each vessel. This would lead to an hourly usage of 31 hours per year or 0.0849hours per 24 hours. This is misleading however as for every use the battery bank will have to supply 3800W of electric charge to allow the recovery of a vessel. This will require a very large battery bank although the number of panels required will be less due the large amount of time the battery bank can be recharged over.
Device Voltage
(V)
Power
(W)
Length of use
(hours/day)
Power use over 24
hours (Wh/day)
Superwinch LP 10000 12 3800 0.0849 322.74
Table 3: Average load for a vessel recovery winch
Outline design The limiting factor in this application will be the size and cost of the battery bank. AGM batteries have been selected for this application as they are protected from leakage and can manage the rapid discharge rates required by this application. As this application is to power an intermittent and intense load, the battery bank has to be sized in order to allow the winch to operate for one hour at full capacity I.e. the battery bank is required to supply 3800Wh. This is the rating that should be carried forward to size the battery bank. The temperature compensation and depth of discharge values in table below are taken from the UPG UB8D unit datasheet
36
35 http://www.innovation-engineering.co.uk/LP8500_recovery_winch.htm
36 http://upgi.com/Themes/leanandgreen/images/UPG/ProductDownloads/45964.pdf
The number of days of autonomy has been set to 3 to account for variations in irradiance and maintenance downtime.
AC loads 0 Wh/day 0 Wh/day
Inverter efficiency 0 % 0 Wh/day
DC loads 3800 Wh/day 3800 Wh/day
Number of days of autonomy 3 days 11400 Wh
Temperature compensation 98% % 11633 Wh
Depth of discharge 75% % 15510 Wh
Voltage 12 V 1293 Ah
Battery bank requirements: 1.29 kAh
Table 4: Battery bank requirements for the vessel recovery winch running at 3800W for 31 days per year
The UPG UB8D provides 150Ah over a 1 hour but after 12 months this would reduce to 96Ah. In addition, at 75% discharge, the battery would reduce to 60% of original Ah capability after 350 cycles. To allow a years’ worth of usage for this application it is estimated that a bank of 14 UPG UB8D batteries would be required. This would provide 1344Ah after a year’s operation (96Ah*14units). The panel system will be specified to allow for full charging of the battery bank every 0.0849 a day. Note this number will be higher than the average consumption calculated in Table 4 as the battery bank has been oversized.
V ) lectricity use per day W = ( * I * E
3800)* 0.084912 W = ( *
871Wh/day W = 3
This can now be inputted into the standard calculation table.
Total solar resource 3871 Wh/day
Battery efficiency 85% %
PV array efficiency 75% %
System efficiencies 64% %
Shading efficiencies 90% %
Overall efficiencies 57% %
PV system - efficiency losses 6747 Wh/day
Peak sun hours 5.50 Hours/day
PV system sized to available energy 1227 W
Table 5: Panel array assessment for the vessel recovery winch running at 3800W for 244 days per year
Shading efficiency has been set to 90% to account for shading from the water tower and surrounding relief with other efficiencies being standard across applications.
This calculation estimates that 1630W would be required to power the battery bank and load. This could be supplied by 17 SolarTech SPM100P-TS-F panels. There are higher wattage panels
37
available but these generally operate at 24V rather than the 12V required by the winch. Outline cost estimates
Component Number of units Cost per
unit Total cost
Superwinch LP 10000 1 $481.99 38
$481.99 UB8D Universal 12V 14 $483.83
39$6773.62
SolarTech SPM100P-TS-F 17 $263.00 40
$4471.00 Total cost: $11,726.50 Table 6: Indicative costs for the main pieces of equipment required
The costs of this application are extremely large especially as the battery bank, the largest cost component of the system, will need to be replaced or augmented every 12 months. Other elements have not been considered in this outline cost calculation include wiring, panel mountings, charge controllers, a concrete plinth for the winch, caballing for the winch and maintenance.
Strengths Weaknesses
● Improved health and safety as fishermen will not be required to pull ropes manually, there would be no requirement to stand close to the cable as it hauls vessels and reduced risk of snapping of winch cable due to consistent load applied and appropriate design
● Reduce the number of people required to haul vessels out
● The prohibitively high capital cost of the system
● Maintenance of the winch cable will be required
● The requirements for the battery bank to be replaced every 12 months
● There is no contingency for if there are a number of boat haul outs required over a short period of time.
Opportunities Threats
● There is an opportunity to develop a system that could be applied across the region and in other developing countries
● The negative perception of winches and haul out aids due to past accidents threatens the acceptance of the idea
● No current evidence or case studies to draw on to prove the concept
37 http://www.mrsolar.com/content/pdf/Solartech/SPM100P-TS-F.pdf
38 http://www.superwinch.com/p/lp10000-%E2%80%93-10-000-lbs-12v
39http://www.batteriesasap.com/ub-8d.html
40 http://www.mrsolar.com/solartech-spm100p-ts-f-100w-12v-solar-panel/
● Winch technology is very well established and widely available as is solar technology
● There is currently no appetite to change the method of boat haul out
6.3.2 Fishermen- Jib crane/winch
Application title Jib crane/winch for vessel unloading
Stakeholder
group
Association Gremio de Pescadores Artesanales ARPA (Association of local fishermen)
Application description
The fish quay in Lobitos services approximately 61 vessels but is equipped with minimal facilities. The quay does not have a handrail and there is no fresh water supply or power supply (other than to the lights) on the quay. The installation of a solar powered jib winch for lifting fish boxes from the decks of boats and tender vessels up onto the fish quay would provide a solution to the current practice of using nylon ropes. Water for cleaning the fish and keeping them cool is also collected using ropes. The current method has many potential dangers exacerbated by the fact that there is no hand rail and there are no aids/ pulleys to a) reduce the load that is being hauled to quay level and b) protect the rope from rubbing on the quay edge potentially forming weaknesses and potential snapping risk. There are many examples of electric winches being used for lifting boxes of fish with the power required lift these loads appropriately low to be serviced by a solar installation. The ARPA are not a cash rich organisation with a very modest turnover from subsidies paid by fishermen. This means that any application should require very low maintenance and running costs. The ARPA are able to apply for funding from a variety of sources including the Municipality and the Ministry of Production so larger capital investments are possible if there is a strong case to support them.
Photograph 5: Sorting of catch and gutting of fish in the working area at the end of the pier
Photograph 6: Sorting of commercial fish. The concrete tub is filled with water (by hand) to clean the fish and sort them
Photograph 7: Tender boat landing fish boxes
Photograph 8: Sorting of commercial fish
Case studies
There are no readily available case studies of using solar power to power a jib winch. This could be for several reasons including that the wattage required to power such a system would necessitate a very large and costly solar installation. This may also be due to the fish quays generally having ready access to conventional electrical supply (e.g. grid connection and diesel generators) that are utilised over renewable energy systems. For smaller loads there are a number of hand winches on the market that are cheaper, easier to operate and easier to maintain than electrical winches that may be powered by solar energy. An example of a manual winch that could lift fish boxes and water canisters is the Lifting safety 125kg CDA-3131 manual jib crane .
41
Outline design
41 http://www.liftingsafety.co.uk/product/counterbalance-davit-arm-3131.html
Visual site survey and mode of operation The area at the seaward end of the quay where this application is situated is very open with the sea to the north west, open beach north east and south west. There is an area of relief to the east that would restrict the early morning sun but would cause little issue if the panels were mounted high enough. The most obvious location to mount the system is at the end of the fish quay which is particularly open. There is potential to mount the panels on top the ARPA production building (6-7m high) however this would require a cable run of approximately 300m increasing cost and electrical losses. Accordingly the PV system should be situated at the end of the fish quay, close to the jib winch. Mountings are required for the panels and battery bank. There are numerous solar panel mounts such as the IronRidge SP/01 Universal Side of Pole Mount which offers a durable option at low
42
cost. Battery cabinets are required to protect the battery bank. These should be secure, weather tight and incorporate good ventilation to minimise gas build up. A suitable cabinet for the size and number of batteries in this application is the Midnite Solar - MNBE-DR3 Battery Enclosure .
43
This application is suited to a flexible stand-alone solar system as there is no readily available alternative source of grid power. A conservative approach will be taken when assessing the load profile as the crane may not be used in a regular predictable manner. Load characterisation The concept of a jib winch is similar to the vessel recovery winch explored in 6.3.1 but with the addition of a frame to allow the handling of loads in the vertical plane. Jib frames are usually articulated and can be extended to allow the handling of varied loads from platforms at one level to another. The winch that has been specified in this example is the Superwinch C1000 . This has a lifting
44
capacity of 454kg running a 1.3hp motor at 12V DC. The datasheet for this winch states that the motor requires 80 Amps when running at 100% capacity (454kg) and 50 Amps when running at half capacity (227kg). The loads carried in this application will be much lower than the capacity of the winch (e.g. fish boxes weighing approximately 20kg water containers weighing approximately 30kg) however there are few other winch options that run at 12V DC. The system will be used periodically by the fishermen to retrieve water and fish boxes as boats land their catch. It is assumed that 1-2 boats land per day and that the winch will be used steadily for a period of 1.5 hour per vessel. The hours of use per day have been stated as 2 hours as the winch will not be in constant use throughout unloading of the vessel (accounting for shuttling of tender vessel and loading/unloading). The wattage of the winch at 50% lifting capacity is calculated as:
P = V * I
42 IronRidge SP/01 Universal Side of Pole Mount
43 http://www.solarpenny.com/Midnite-Solar-MNBE-DR3-Battery-Enclosure-716109.htm
44 http://www.innovation-engineering.co.uk/crane.htm
2 0 P = 1 * 5
Watts00 P = 6
Device Voltage (V)
Power (W)
Length of use (hours/day)
Power use over 24 hours (Wh/day)
Superwinch C1000 12 600 2 1200.00
Table 7: Average load for a job winch
A frame is also required to mount the winch onto. This has been requested from Lifting Safety with description and quote supplied in Appendix E. The frame is capable of handling 50kg and has a 90o left/right swing with 1m reach. The frame is freestanding on a counter balanced base to allow it to be moved around the quay. Outline design Temperature conversion data and depth of discharge have been taken from the Universal UB8D 230Ah battery . This is an AGM battery that can handle a rapid discharge over a short period of
45
time. At 0.2C (5 hours discharge) this is stated as 212.5Ah. The battery has been over specified to a high degree due to the short shelf life of AGM batteries. After 12 months of operation, the battery is predicted to only operate at 64% of its original capacity. With this in mind, 3 batteries would be required for this system which after a year would still be outputting 637.5Ah at 0.2C. The specified battery would be able to supply the application at calculated power usage for 18 months, at which point a new battery system should be considered. In addition, after approximately 400 charge cycles, the battery system would only be operating at 45% of the original capacity. For this reason the depth of discharge has been set reasonably high at 70%. The number of days of autonomy has been set to 3 to account for any reduction in irradiance or maintenance down time for the panels.
AC loads 0 Wh/day 0 Wh/day
Inverter efficiency 0 % 0 Wh/day
DC loads 1200 Wh/day 1200 Wh/day
Number of days of autonomy 3 Days 3600 Wh
Temperature compensation 98% % 3673 Wh
Depth of discharge 70% % 5248 Wh
Voltage 12 V 437 Ah
Battery bank requirements: 0.437 kAh
Table 8: Battery bank requirements for a jib winch running for 2 hours per day
The panel array required for this application has been calculated at approximately 350W. The
SolarLand SLP140-12 produces 140 at 12V under standard test conditions. 3 of these panels 46
45 http://www.mrsolar.com/content/pdf/Universal/UB8D.pdf
46 http://www.mrsolar.com/content/pdf/SolarLand/Panels/SLP140-12.pdf
connected in parallel would create 420W at 12V and would be sufficient to power this application
and battery bank.
Shading efficiency has been set to 98% as there are very few obstructions at the end of the fish
quay where this system will be placed.
Total solar resource 1200 Wh/day
Battery efficiency 85% %
PV array efficiency 75% %
System efficiencies 64% %
Shading efficiencies 98% %
Overall efficiencies 62% %
PV system - efficiency losses 1921 Wh/day
Peak sun hours 5.50 Hours/day
PV system sized to available energy 349 W
Table 9: Panel array assessment for a jib winch running for 2 hours per day
Outline cost estimates
Component Number of units Cost per unit
Total cost
Superwinch C1000 1 $601.87 47
$601.87 Wire Rope 15.2m 1 $86.89
48$86.89
CMU lifting davit 1 $5693.53 49
$5693.53 IronRidge SP/01 Universal Side of Pole Mount
3 $80.73 $242.19
Midnite Solar - MNBE-DR3 Battery Enclosure
1 $845.00 50
$845.00
Universal UB8D battery 3 $478.00 51
$1434.00 SolarLand SLP140-12 panel 3 $314.65
52$943.95
Total cost: $9847.43 Table 10: Indicative costs for the main pieces of equipment required
The costs of the battery bank are the largest component of the overall cost and would have to be replaced or augmented approximately every 18 months. Other elements to consider would be the
47 http://www.superwinch.com/p/c1000-remote-solenoid-1-000-lbs-12v?pp=12
48http://www.superwinch.com/p/wire-rope-1-4-x-50-6-4mm-x-15-2m-for-s5000/industrial_crane-
series
49 See quote in appendix folder. Note converted from £ to $ on 23/06/2015 at exchange rate of
1.57 dollars to the pound
50 http://www.solarpenny.com/Midnite-Solar-MNBE-DR3-Battery-Enclosure-716109.htm
51 http://www.mrsolar.com/universal-power-12v-230ah-agm-battery/
52 http://www.mrsolar.com/solarland-slp140-12-140w-12v-solar-panel/
maintenance requirements of all components as they will be exposed to salty conditions and could be susceptible to corrosion. Cabling, charge controllers, auxiliary works and maintenance have not been considered in this cost calculation.
Strengths Weaknesses
● Improved health and safety with reduces risk of people falling off the quay and ropes breaking causing injury
● Could improve productivity of the fishermen requiring less people to unload and allowing quicker turnaround times
● There are no ready-made systems or case studies that can be drawn on to prove the concept
● Careful management of usage in line with the battery charge state will be required to ensure the longevity of the battery (this is due to there being no obvious schedule for use of the application).
Opportunities Threats
● There is an opportunity to develop a system that could be applied across the region and in other developing countries
● Winch technology is very well established and widely available as is solar technology
● The negative perception of winches and haul out aids due to past accidents threatens the acceptance of the idea
● Maintenance of the all components would be required as the area is exposed and could be susceptible to corrosion
6.3.3 Fishermen- Lighting of fish quay
Application title Lighting of the fishing quay
Stakeholder
group
Association Gremio de Pescadores Artesanales ARPA (Association of local
fishermen)
Application description
There are several facilities to support the operations of the Lobitos artisanal fishing fleet. These include a car parking, processing building, a quay and road access to connect these facilities. Street lighting is used to illuminate these areas during the hours of darkness to allow safe operations. The usual pattern for day boats is to launch very early in the morning, while in darkness, and return around mid-morning. Lighting is also seen to increase security of the facilities. The ARPA pays for the electricity that is used in the processing building and lighting. The approximate monthly bill is 150s/ per month. There are 12 outside lights in total using 80 watt bulbs which run from the hours of 7pm to 5am daily.
The lights were installed in mid 1990s and are grid connected through agreement with Enosa. Through initial usage the ARPA noted that the bill was more expensive than they could afford (no details given on what the cost was). As a result the Ministry of Production scoped, designed and installed 6 solar panels, two charge controllers and two batteries (see photos) in 1995. This system was tested after installation but failed after 2 days of use. The fishermen had been supplied with no instructions and no contact at the Ministry of Production to repair the PV installation. The lights were reconnected to the grid system but have been wire so that only 4 lights are used in order to reduce the electricity bill. The PV installation was removed after the panels were vandalised and two of the panels were stolen. While in Lobitos I tried to do some tests on the panels to see if the problem could be diagnosed. I wired the panels to a charge controller and batteries to see if any of the indicator lights came on (the battery and charge controller both had indicator lights to signify the status of the installation). The system showed no lights when wired straight to the battery or through the charge controller. I checked to see if there were any fuses in the panels or charge controller that could be replaced. Without a multi-meter/volt-meter it is not possible to accurately diagnose the problem. A new system utilising more up to date technology will be scoped under this application use of the full lighting system. This project may also involve changing the bulbs in the lamps to energy saving bulbs or LEDs. This application would require careful training of the fishermen into the operation and maintenance of equipment to build trust and allow appropriate maintenance to be done. Capital costs may be available through grant funding from the Municipality or Ministry of Production.
Photograph 9: View down the fish quay to the fish production facility
Photograph 10: Working area at the end of the fish quay. Lighting in the background
Photograph 11: View down the fish quay from the production building
Photograph 12: View down the fish quay back to the production building
Literature review
The Food and Agriculture Organization of the United states have produced a technical paper on 53
the planning, construction and management considerations required for small and medium scale fishing ports. There is a section detailing considerations of using PV for lighting of fishing port facilities. The document notes that outdoor lighting systems are usually stand-alone systems noting the use of gel batteries and recommend those fittings are aluminium and stainless steel to avoid corrosion. In this application the lighting will be external and illuminate an area that accommodates both vehicular and pedestrian traffic. As such it is appropriate to look at standards and examples of street lighting. With the advances made in cost reduction of LED lighting, the energy requirements of outdoor lighting systems have reduced dramatically. LEDs have a significantly longer life of approximately 50,000 hours, well over twice that of conventional street lights . In addition power usage can be
54
up to 50W less than conventional lighting systems whilst providing a similar lighting performance
55
53 http://www.fao.org/publications/card/en/c/994c5499-4a04-525e-81f5-3d6268675699/
54 http://apps1.eere.energy.gov/buildings/publications/pdfs/alliances/outdoor_area_lighting.pdf
55 http://apps1.eere.energy.gov/buildings/publications/pdfs/alliances/outdoor_area_lighting.pdf
There are several integrated PV and LED luminaire units available on the market from as little as $600 . In addition, companies such as Philips offer tailor made lighting systems based on:
56 57
● Application (road, residential, area, security etc.) ● Geographical location ● Required light levels ● Required uptime (number of hours of light) ● Possibility of dimming the light (during off-peak hours)
Outline design
Visual site survey and mode of operation In the current installation, 12 lights cover the pier (which is 314m long by 7-12m wide) and the car park area. There are existing poles which are approximately 5 high. For a PV array of the size potentially required for this application, the production facility roof would be an appropriate mounting point. The only potential shading obstructions in the area are from the water tower situated to the north and an area of relief to the east. These obstructions should be taken into account in the panel sizing calculations. The system will run as a stand-alone system to allow 12V LED units to be utilised. The lights will be connected in a string to minimise the amount of equipment required to light the area. A grid fallback system would be a potential option that could be investigated however the load is of a scale and predictable for an optimised stand-alone solution to be utilised. Outline design In order to reduce the number of LED units and overall costs of the installation, a wide angle luminaire has been specified, the 27W-LED-Street-12VDC-120-BA . This covers a wider footprint
58
from a single source than many other LED lights on the market. The units use 2.3 amps at 12V of DC. The unit provides 2800 lumens with the area inside the beam angle providing enough light to read. The LED unit has lighting angle of 120o in both lateral and longitudinal planes. The footprint covered by the stated 2800 lumens is calculated as:
an(x)t = ao
56
http://ledcent.en.made-in-china.com/product/AbcnFdsJlypj/China-15W-160W-Solar-Street-Light-
with-Solar-Panel-Controller-and-Battery.html
57
http://www.lighting.philips.com/pwc_li/main/application_areas/assets/pdf/Philips_solar_road_lig
hting_solutions.pdf
58 http://www.led-cfl-lighthouse.com/page/1449301
an (60) t = 5o
an (60) o = t * 5
.7m o = 8
This means that a footprint of 17.3m by 17.3m will be illuminated from this light source. To fully illuminate the whole pier 18 of these units will be required to full highway specification. In order to reduce power requirements, fit in with the pattern of lighting poles available and to account for spill-over from the fully flooded footprint, a string of 8 LED units will be calculated. This will be sufficient to light the pier and if appropriate, a duplicate system could be used to light the car park and production buildings. Length of use has been set to 10 hours per day to replicate original system.
Device Voltage
(V)
Power
(W)
Length of use
(hours/day)
Power use over 24
hours (Wh/day)
27W-LED-Street-12VDC-120
-BA 12 27 10 270.00
Table 11: Average load for a single LED light
Outline design
The full string of 8 lighting units requires 2160 Wh/day. A bank of 8 Universal UB-30H 93Ah (at 59
C10) Gel batteries would be sufficient in this case. These batteries operate at 100% temperature compensation efficiency at 250C. As the batteries will be housed in the production facility, the temperature can be moderated to allow full performance of the battery and hence the temperature compensation has been set to 100%. The depth of discharge has been set to 75% to allow approximately 450 cycles. The number of days of autonomy in this system has been set to 3 to account for any outages of the PV array or prolonged spells of limited irradiance.
AC loads 0 Wh/day 0 Wh/day
Inverter efficiency 0 % 0 Wh/day
DC loads 2160 Wh/day 2160 Wh/day
Number of days of
autonomy 3 Days 6480 Wh
Temperature compensation 100% % 6480 Wh
Depth of discharge 75% % 8640 Wh
Voltage 12 V 720 Ah
Battery bank requirements: 0.72 kAh
59 http://www.mrsolar.com/content/pdf/Universal/UB30H.pdf
Table 12: Battery bank requirements for a string of 8 luminaires
The panel array has been calculated needing to be a 684W system in order to meet the
generation requirements of the battery bank and load. The shading efficiencies have been set at
90% to account for the shading effect of the water tower assuming that the panels will be
mounted on the roof of the production building. Seven 100W Solartech SPM100P-TS-F 100W 60
panels connected in parallel would generate 700W and therefore be sufficient to supply this
application.
Total solar resource required 2160 Wh/day
Battery efficiency 85% %
PV array efficiency 75% %
System efficiencies 64% %
Shading efficiencies 90% %
Overall efficiencies 57% %
PV system - efficiency losses 3765 Wh/day
Peak sun hours 5.50 Hours/day
PV system sized to available energy 684 W
Table 13: Panel array assessment for a string of 8 luminaires
Outline cost estimates
Component Number of units Cost per unit
Total cost
27W-LED-Street-12VDC-120-BA luminaire
8 $375.00 61
$3000
Universal UB-30H battery 8 $225.00 62
$1800 SolarTech SPM100P-TS-F panel 7 $263.00
63$1841
Total cost: $6641 Table 14: Indicative costs for the main pieces of equipment required
Table 12 summarises the main costs of this application. Items that have not been included are battery cabinets (the batteries may be stored inside the production building), panel fixings, light fixings and wiring runs. These elements will be considered in more detail if taken through to detailed design. Another element that could be investigated is lighting sensors that may only turn the lights on when movement or presence is sensed and dim the lights when there is no presence. This would
60 http://www.mrsolar.com/content/pdf/SolarLand/Panels/SLP085-12U.pdf
61 http://www.led-cfl-lighthouse.com/page/1449301
62
http://www.mrsolar.com/universal-power-12v-98ah-gel-battery/?page_context=category&facete
d_search=0
63 http://www.mrsolar.com/solartech-spm100p-ts-f-100w-12v-solar-panel/
have the effect of reducing the amount of time that the system is in operation and hence the PV system size
Strengths Weaknesses
● Improves health and safety as well as security around the fish quay and production building
● Has potential to reduce the electricity costs to the ARPA
● There is a predictable and regular load that would could be well serviced by a PV system
● High capital costs ● The batteries will need to be replaced
after approximately 450 cycles ● If the PV system failed, the LEDs would
not operate with grid electricity unless a step down inverter was installed
Opportunities Threats
● Could be designed as a stand-alone system to be used for other applications e.g. as street lighting.
● The lighting would have to be disconnected from the grid to allow the system to operate (without supply of an inverter) which would mean no contingency and inhibitive costs to reconnect to the grid.
● Would have to build trust with the fishermen as they may distrust the technology after the previous system failed
6.3.4 Fishermen- Pumping water for use in water tower
Application title Pumping water for ARPA production building water tower
Stakeholder group
Association Gremio de Pescadores Artesanales ARPA (Association of local
fishermen)
Application description
Water is supplied to the production facility via a water tower. This was built to service the planned processing plant but it currently just supplies water for toilet facilities in the ARPA offices. Water is delivered by truck once a month and pumped up to the water tower using a small 370W hydro-pump (see Photograph 13). The tank takes approximately an hour to fill. The pump used for this activity currently runs off the mains but solar energy could be used to charge a battery to supply the pump, reducing the electricity bill that the ARPA have to pay.
Photograph 13: Pump shown during meeting with the fishermen
Photograph 14: Specifications of the pump used for pumping water into the water tower
Photograph 15: The ARPA production building with water tower to the left of the photo
Photograph 16: Water tower in the background
Case studies and literature review
Practical Action has produced guidance on solutions for water pumping including utilising PV as a power source . The benefits of using solar PV to perform this pumping activity include:
64
● no fuel costs ● low maintenance ● easy installation ● long life (20 year)
Negatives include
● high capital costs ● water storage is required for cloudy/non sunny periods ● repairs often require skilled technicians
64 http://practicalaction.org/pumping-water-by-solar-power
The report highlights that the any PV system should be sized relative to the pump specifications and characteristics to ensure efficiency. In this application the pump runs on single phase AC meaning that an inverter is required to convert the DC current supplied by a solar system to AC. Inverters can also modify the output frequency from the PV system to optimise the power output to the load on the pump. The Practical Action guidance states that it is important to supply the most efficient pump available as the difference in cost between the poor pump and a very efficient pump is much less that the additional cost required for a larger PV panel. In this case, as the water is being delivered monthly and pumped over a short time, more efficient pumps would potentially increase the length of time for deliveries to take place and increase delivery costs. Therefore a PV system using the existing pump working under a similar timeframe has been investigated.
Outline design
Visual site survey and mode of operation There area that this application will be set in is very open with the sea to the north west, open beach north east and south west. There is an area of relief to the east that would restrict the early morning sun but would cause little issue if the panels were mounted high enough. There are two potential mounting points for the panels: on top of the ARPA production building (6-7m) or on top of the water tower (approximately 10m). The water tower is preferable in this case to keep the panels closer to the rest of the system and also to avoid shading that the water tower would cast onto the production building roof. This application is suited to a stand-alone solar system due to the long length of time available for batteries to recharge (reducing risk of solar irradiance fluctuations having a large effect of power output) and the ease with which the pump could be switched back to the grid supplied electricity in the event of PV system downtime. The specifications of the current pump are listed in the table below. The length of use in hours per day is based on the interview with the ARPA in which they stated that the water tower was filled once every month and takes approximately an hour to fill. This gives the average power required per day for the application at current usage levels. The pump operates at 220V AC on single phase so a single phase inverter is required. Load Characterisation
Device Voltage
(V)
Power
(W)
Length of use
(hours/day)
Power use over 24
hours (Wh/day)
Existing pump 220 370 0.0329 12.16
Table 15: Load characterisation for existing water pump
As this application is to power a very intermittent and intense load, the battery bank has to be sized to allow the pump to operate for one hour at full capacity. Over a single 1 hour use of the pump, the battery bank is required to supply 370Wh of power. This is the rating that should be carried forward to size the battery bank. Outline design
Temperature conversion data and depth of discharge have been taken from the Universal UB4D 65
200Ah battery . This is an AGM battery that can handle a rapid discharge over an hour operating 66
at 120Ah at 1C. The battery has been over specified to a high degree due to the short shelf life of AGM batteries. After 12 months of operation, the battery is predicted to only operate at 64% of its original capacity. The specified the battery would be able to supply the application at calculated power usage for 12 months only at which point a new battery system would be required. As the pump operates on single phase AC current, an inverter is required to link the battery to the load. The inverter selected is the Solar Power Maker SPM-MC1000 . This has the flexibility to
67
output at 220V at 60Hz to a power rating of 1000W. The inverter efficiencies are stated as >93% which has been included in the table below. The number of days of autonomy has been set to 0 due to the very long period available for charging the battery. This would negate the need to account for variations in solar irradiance or small scale maintenance.
AC loads 370.0
0 Wh/day 370 Wh/day
Inverter efficiency 93% % 398 Wh/day
DC loads 0 Wh/day 398 Wh/day
Number of days of autonomy 0 days 398 Wh
Temperature compensation 98% % 406 Wh
Depth of discharge 70% % 580 Wh
Voltage 12 V 48 Ah
Battery bank requirements: 48 Ah
Table 16: Battery bank requirements for the water pump running for 1 hour once a month
The panel system should now be specified to allow for full charging of the battery bank every month (assumed as 30 days). Note this number will be higher than the average consumption calculated in Table 16 as the battery bank has been oversized.
(Ah of the battery bank) W = V * I
200)/3012 W = ( *
0Wh/day W = 8
This can now be inputted into the standard calculation table. Total solar resource required 80 Wh/day
Battery efficiency 85% %
PV array efficiency 75% %
65 http://www.mrsolar.com/content/pdf/Universal/UB4D.pdf
66 http://www.mrsolar.com/content/pdf/Universal/UB4D.pdf
67 http://www.solarpowermaker.com/phase-inverter?search=single phase inverter
System efficiencies 64% %
Shading efficiencies 90% %
Overall efficiencies 57% %
PV system - efficiency losses 139 Wh/day
Peak sun hours 5.50 Hours/day
PV system sized to available energy 25 W
Table 17: Panel array assessment for the water pump running for 1 hour once a month
The shading efficiencies for this application have been set at 98% assuming that the panels will be mounted on top of the water tower. The 25W Solarland SLP025-12U would be an appropriate
68
panel to use for this application. Outline cost estimates
Component Number of units Cost per unit
Total cost
Universal UB4D battery 1 $325 69
$325 Solar Power Maker SPM-MC1000 1 ~$84.50
70$30
25W Solarland SLP025-12U panel 1 $103.04 71
$103.04 Total cost: $458.04 Table 18: Indicative costs for the main pieces of equipment required to supply water pump
Estimated costs of the main equipment for this application is approximately $460 not including shipping, cables, mounting or maintenance. The largest cost component is the battery which will have to be replaced annually.
Strengths Weaknesses
● The system is relatively cheap ● The application can be run using single
components rather than arrays meaning less cabling and maintenance
● The requirement to purchase a new battery every year mean that there savings will be modest if any over using grid supplied electricity
● The high discharge rate is not suited to stand alone solar PV systems
Opportunities Threats
● There is a good local solar resource with numerous secure and unobstructed areas to mount panels.
● The pump will be able to be reconnected to grid power if the solar system fails
● The application would be reliant on the users knowing how to use the equipment and replacing the battery after a year
● The application would push the equipment to the limit of its
68 http://www.mrsolar.com/content/pdf/SolarLand/Panels/SLP025-12U.pdf
69 http://www.mrsolar.com/universal-power-12v-200ah-agm-battery/
70 http://www.solarpowermaker.com/phase-inverter?search=single phase inverter
71 http://www.pvpower.com/Solarland-25w-Multi-solar-panel-SLP030-12U-1-1.aspx
operational range meaning that faults may be more common
6.3.5 Residents/small businesses- Use of solar to offset electricity bills
Application title Use of solar to offset electricity bills for residents or small businesses
Stakeholder group
Residents/small businesses
Application description
This application is proposed to raise awareness and highlight the opportunity to residents and
small business owners in Lobitos of the potential savings on electricity bills. In order to
demonstrate potential costs/benefits, an example has been selected based on a typical
household/small business.
Jesus Vite Taume- owner of a small shop and catering business
Jesus owns and runs a convenience store from his property in the residential area of Bellavista.
On occasion he will cater for municipality meetings and events but this is very small scale.
The main electrical loads are 3 fridges, a TV, lights, charging of 2 mobile phones and cooking
appliances. He is very aware of his energy use as this is his main business outgoing. He tries to
manage electricity use by consolidating stock and switching off fridges.
He has family who live in Talara and stated that electricity is more expensive in Lobitos due to the
distance from the main grid and the relatively small usage (no industry or large scale users other
than hostel owners). All electricity is metered and managed by ENOSA. There is also a charge
proportionate to the energy bill that pays for street lights and taxes.
The unit price of electricity is gradually rising and all parts of the bill are increasing including taxes
and street light payments. If a bill is not paid for 2 months the electricity is cut off with
reconnections being charged on top of the outstanding balance.
He has a good perception of solar applications because the phone boxes used to be powered
using solar electricity and he tapped into electricity generated by these illegally to offset his own
electricity usage.
Literature review
The IEA PVPS Task 9 aims to “increase the deployment of PV services for regional development”.
This initiative has produced a report exploring issues in “Pico Solar PV Systems for Remote
Homes” . This report draws on experiences to date and provides examples of pico solar systems. 72
The design of the solar PV system detailed in this report are smaller than this application however
a lot of the lessons are still valid especially in respect to the importance of demand assessment,
client buy in and financing models for PV equipment.
Key lessons in this report include:
● The project and the long-term commitment of the stakeholders are vital for the success of
the PV project 73
● The size of system installations needs to be determined based on demand—which in turn
needs to balance three often conflicting viewpoints from : 74
72 http://www.iea.org/media/openbulletin/Pico_Solar_PV_System.pdf
73 Finucane, Jim, & Purcell, Christopher, PV for Community Service Facilities: Guidance for
Sustainability, AFREA and World Bank, Washington D.C., 2010
74 World Bank, Rural electrification in Africa, Washington D.C., USA, April 2012
o International financial institutions (funders), often oriented toward basic needs and
cost-benefit analyses;
o end-users, who often list TV viewing the highest priority; and
o engineers, who typically determine standardized need levels and system sizes.
● The lack of lasting maintenance structures is a significant weakness of PV system service
delivery in many programmes.
In terms of financing models noted by the IEA , these can be broken down into three categories: 75
1. Dealer Credit, where the client enters into credit with the PV system dealer. Upon paying off the credit the client becomes the owner of the equipment. Under this model, analysis of the life cycle of the PV system and potential maintenance/replacement component such as batteries should be consider when determining the credit term
2. End-user Credit, where credit to by the PV equipment is obtained by the user from a third party such as a bank. Usually the end-user becomes the owner of the system immediately, but this can be delayed until all payments are made. The PV system can be used as collateral against the loan.
3. Lease / Hire purchase, where the equipment is leased to the client for a term at the end of which the client may or may not own the equipment depending on the agreement. During the term of the lease the lessor is responsible for any maintenance or repairs
The IEA report also highlights some common appliances and estimates usual power usages.
● A small TV (7 inch LCD) requires a power of less than 10 watts. ● The energy consumption of a refrigerator depends size, efficiency, temperature setting
and the temperature of the room in which it is placed. In the literature, refrigerator consumption values of 1000-1300 kWh/year (3-4 kWh/day) are quoted [Hagan, 2006]. The power demand of standard (compression type) refrigerator is between 50 and 100 W, depending on size.
The IEA have reported on funding mechanisms to finance uptake of PV systems in developing countries as well as real case studies of where these have been applied .
76 77
75 http://www.iea.org/media/openbulletin/Pico_Solar_PV_System.pdf
76
https://energypedia.info/images/7/74/Financing_Mechanisms_for_Solar_Home_Systems_in_Dev
eloping_Countries.pdf
77
http://www.google.co.uk/url?sa=t&rct=j&q=&esrc=s&frm=1&source=web&cd=1&ved=0CCcQFjAA
&url=http%3A%2F%2Fiea-pvps.org%2Findex.php%3Fid%3D155%26eID%3Ddam_frontend_push%
26docID%3D206&ei=jJZTVdHZKoq1sQSB6oHYBg&usg=AFQjCNGS6BuQHtlSWSQ4vzE8IiKXK8_Cmw
&sig2=AI9XonlHW9Z_thmXCEZ9Lw&bvm=bv.93112503,d.cWc
Practical Action have produced numerous technical resources to support the installation of PV installations at reduced cost .
78
Outline design
Visual site survey and mode of operation The Bellavista area of Lobitos is relatively built up with single and 2 storey buildings. The buildings are generally constructed of thin wooden walls with corrugated metal roofs. It would be possible to mount solar panels on these roof structures but extreme care is required to ensure that the roof can take the weight of workers during installation and maintenance. Specific fixings are required that are compatible with roof mounted installations with rubber/plastic caps used around fixings to ensure the roof remains watertight. Approximately 50m2 of roof space is available on the roof of Jesus’s house and restaurant. The roof is west north west facing and is not shaded by other trees or buildings. Space would need to be found inside the building to house the battery bank (therefore Gel or AGM batteries would be appropriate due to the reduced gas emissions) and connection to the main circuit board. It is proposed that the system will run as a stand-alone system supplying a dedicated circuit to the kitchen and living room/shop area to power the more power hungry appliances. A grid tied back up system would also be an appropriate solution but this will be explored further if this case sudy is taken forward for detailed design. Load assessment Using the information gain from a survey of the Jesus’ property the loading assessment has been created below. The estimated power usages have been taken from Appendix C of the Solar Electricity Handbook .
79
It is estimated that the fridges will only be drawing power for 12 hours a day. This is due to the fridge motor only operating to maintain a temperature rather than operating permanently which (assuming efficient thermal insulation properties of the fridge casing). Device Voltage
(V) Power (W)
Length of use (hours/day)
Number of items
Power use over 24 hours (Wh/day)
350 litre fridge 80
220 125 12 3 4500
CRT TV 21" 81
220 100 4 1 400
Food mixer 220 130 1 1 65
78
http://answers.practicalaction.org/our-resources/item/small-scale-off-grid-solar-pv-installation-m
anual
79 SEH
80 http://michaelbluejay.com/electricity/refrigerators.html
81 http://energyusecalculator.com/electricity_lcdleddisplay.htm
Table 19: Load profile for an example small business owner
Outline design In order to minimise inverter inefficiencies the system has been designed at 24V. This can be achieved by wiring two 12V batteries in series. An inverter will be required as the appliances all currently run on AC current at 220V from the main grid system. The CTP-5000W inverter is sufficient for this application taking 24V DC and converting to 220V AC at single phase and is rated at 5000W . 85% efficiencies have been applied to the calculations as stated in the specification of
82
this inverter. The number of days autonomy has been set to 1 due to grid connection still being maintained. If there is a break in supply then loads can be re-connected to the grid circuit. This reduces the requirement of the battery bank significantly. Some level of storage is required however to power loads at night and through overcast periods. Temperature conversion data and depth of discharge have been taken from the MK 8G4D 183Ah 12V battery . This is a Gel battery that at 75% depth of discharge, is capable of providing 750
83
cycles. 4 battery units would be required for this system with two groups of batteries wired in series and then parallel to provide 24V at the required Ah. AC loads 4965 Wh/day 4965 Wh/day Inverter efficiency 85% % 5841 Wh/day DC loads 0 Wh/day 5841 Wh/day Number of days of
autonomy
1 days 5841 Wh
Temperature compensation 98% % 5960 Wh Depth of discharge 75% % 7947 Wh Voltage 24 V 331 Ah
Battery bank requirements: 0.33 kAh
Table 20: Battery bank requirements for an example small business owner
The shading efficiencies for this application have been set at 90% to account for potential shading from surrounding buildings. The 120W SolarTECH SPM140P-S-F 12V panel would be an
84
appropriate panel to use for this application with 11 units required for this application. The panel dimensions are 1466mm by 660mm meaning that approximately 11m2 of roof space is required. Total solar resource required 4965 Wh/day
Battery efficiency 85% %
PV array efficiency 75% %
System efficiencies 64% %
82
http://www.aliexpress.com/item/Factory-straight-sell-5000W-24V-Inverter-Solar-for-off-grid-CTP-
5000W/951502775.html
83 http://www.mrsolar.com/content/pdf/MKBattery/8G4D.pdf
84 http://www.mrsolar.com/content/pdf/Solartech/SPM140P-S-F.pdf
Shading efficiencies 90% %
Overall efficiencies 57% %
PV system - efficiency losses 8654 Wh/day
Peak sun hours 5.50 Hours/day
PV system sized to available energy 1573 W
Table 21: Panel array assessment for an example small business owner
Outline cost estimates
Component Number of units Cost per unit
Total cost
MK 8G4D 183Ah 12V Gel battery 4 $515.00 85
$2600.00 CTP-5000Winverter 1 $631.75
86$631.75
120W SolarTECH SPM140P-S-F 12V panel
11 $ 275.00 87
$3025.00
Total cost: $6256.75 Table 22: Indicative costs for the main pieces of equipment required to reduce small business electricity bill
Estimated costs of the main equipment for this application is approximately $6256.75 not including shipping, cables, mounting, charge controllers or maintenance.
Strengths Weaknesses
● Introduces solar technology to Lobitos
and demonstrates operation and
benefits to those that require solar
technologies
● Reduces resident and small businesses
outgoings and alerts the community to
the potential of solar energy
● The design of the system is such that a
grid connection would be maintained
meaning that autonomy times are
reduced and leave potential for grid fall
back design
● Excess electricity cannot be fed back
into the grid on the micro scale
currently which means that any cost
benefit analysis would have to be
based on savings on paying for grid
electricity
● There may be residual charges for
staying connected to the grid that
would limit the savings made.
85http://www.mrsolar.com/mk-8g4d-183ah-12v-gel-battery/?page_context=category&faceted_se
arch=0
86
http://www.aliexpress.com/item/Factory-straight-sell-5000W-24V-Inverter-Solar-for-off-grid-CTP-
5000W/951502775.html
87http://www.mrsolar.com/solartech-spm140p-s-f-140w-12v-solar-panel/?page_context=category
&faceted_search=0
Opportunities Threats
● There is an un tapped marked in
Lobitos for use of solar panels
● The high price of electricity will lead to
interest in alternative forms of
generation
● There is no conformation as to how
ENOSA will react if there is reduced
electricity demand from grid sources in
Lobitos
6.3.6 Municipality- Lighting of football court
Application title Lighting of the community football courts
Stakeholder
group
Municipal government
Application description
The municipality run and maintain 2 football courts in Lobitos that are floodlit at night. Users of the courts are not charged so the full costs are borne by the municipality. The municipality have expressed an interest fitting a solar installation at the courts to reduce their electricity bills. The benefit of this application would be to lower on-going running costs of the municipality allowing funds to be spent in other areas such as employment schemes.
Literature review
This application draws on the same concepts and equipment as explored under section 6.3.3 which explores solar lighting of the fish quay. Royal Philips Electronics have developed a solar lighting system designed specifically for lighting a football court . The equipment they specify consists of of 8 Fortimo LED module floodlights on
88
four portable poles. The system uses Fortimo LED luminaires with 2 mounted to each pole. A 25W LED luminaire provides 1800 lumens providing an average of 15 lux, on football field 30x15m. The system also specifies 2 batteries which power a 4 hour session for 2 nights without requiring recharging and are estimated to have a lifetime of 5 years. The system is powered by an unspecified number of 80W PV units. Shell have created a novel system of using the kinetic energy that players exert through their feet into electrical energy to power loads such as pitch lighting . The tiles required to do this are not
89
readily available but further enquires can be made if this application is taken through to detailed design.
Outline design
Visual site survey and mode of operation The football court is situated in the Bellavista area of Lobitos. The court is surrounded by 2 covered stands on the long sides, a changing facility on the east side and a wall on the west. The stands are the same height or taller than the surrounding buildings. The roofs over the stands are constructed of corrugated metal sheets and tubular steel frames. They are angler at approximately 15o to horizontal. The changing facility has a flat concrete roof. There is approximately 140m2 on each of the stand roofs and 85m2 on the changing facility roof available to mount panels.
88
http://www.mea.lighting.philips.com/pwc_li/me_en/application_areas/assets/pdf/solar_floodligh
t.pdf
89 http://www.pavegen.com/home
Storage space is available for a battery bank in the in the changing facility although ventilation bricks may need to be added to prevent gas build-up. 5m poles that hold the existing lights are available at the four corners of the pitch to mount new lighting units onto. The system has been designed as a stand-alone system due to the predictable pattern of load and ample storage and mounting space for equipment.
Figure 10: Location plan of football court
Load Assessment The court lighting is currently supplied by 8 street lights. This application proposes replacing these with LED lights to reduce the overall system requirements As with the application to light the fish quay (section 6.3.3), it would be preferable to replace the conventional street bulbs with LED luminaires. This will reduce the PV system requirements and the overall costs. In addition LED bulbs are very reliable meaning minimal maintenance or changing of bulbs would be required. The football court measures 10m by 20m with the furthest possible distance from a pole being approximately 11.5m. Utilising the wide angle luminaire 27W-LED-Street-12VDC-120-BA as specified under the
90
previous application, the coverage of each light is 17.3m by 17.3m assuming 5m poles. This means that 2 lights could be used to light the area but 4 would provide a more comprehensive coverage.
90 http://www.led-cfl-lighthouse.com/page/1449301
Length of use has been set to 6 hours per day to provide light until midnight every night based on the shortest day when the sun sets at approximately 6pm. The load calculation below is for a single light. Device Voltage
(V) Power (W)
Length of use (hours/day)
Number of items
Power use over 24 hours (Wh/day)
27W-LED-Street-12VDC-120-BA
12 27 6 4 162.00
Table 23: Load profile for lighting of the football court
Outline design As the luminaires will be switch from AC conventional bulbs running at 220V to 12V DC LED bulbs, the system has to be robust as it the lights would not work on grid power. Accordingly the number of days of autonomy has been set to 3 to account for panel downtime or reduced irradiance. Temperature conversion data and depth of discharge have been taken from the UB27 86Ah GEL 12V battery . This is a Gel battery that at 50% depth of discharge is capable of providing ~550
91
cycles. 4 battery units would be required for this system. AC loads 0 Wh/day 0 Wh/day
Inverter efficiency 0 % 0 Wh/day
DC loads 648 Wh/day 648 Wh/day
Number of days of
autonomy
3 days 1944 Wh
Temperature compensation 100% % 1944 Wh
Depth of discharge 50% % 3888 Wh
Voltage 12 V 324 Ah
Battery bank requirements: 0.32 kAh
Table 24: Battery bank requirements for lighting of the football court
The shading efficiencies for this application have been set at 90% to account for potential shading from surrounding buildings. The 110W SolarTECH SPM110P-FSW 12V panel would be an
92
appropriate panel to use for this application with 2 units required to service the load and battery bank.
Total solar resource required 648 Wh/day
Battery efficiency 85% %
PV array efficiency 75% %
System efficiencies 64% %
Shading efficiencies 90% %
Overall efficiencies 57% %
PV system - efficiency losses 1129 Wh/day
91 http://www.mrsolar.com/content/pdf/Universal/UB27.pdf
92 http://www.mrsolar.com/content/pdf/Solartech/SPM110P-FSW.pdf
Peak sun hours 5.50 Hours/day
PV system sized to available energy 205 W
Table 25: Panel array assessment for lighting of the football court
Outline cost estimates
Component Number of units Cost per unit
Total cost
UB27 86Ah GEL 12V Gel battery 4 $219.00 93
$876.00 27W-LED-Street-12VDC-120-BA lumiaire
4 $375.00 94
$1500.00
120W SolarTECH SPM140P-S-F 12V panel
2 $ 250.00 95
$500.00
Total cost: $2876.00 Table 26: Indicative costs for the main pieces of equipment required for lighting of the football court
Estimated costs of the main equipment for this application is approximately $2876.00 not including shipping, cables, mounting, charge controllers or maintenance.
Strengths Weaknesses
● This application is a relatively cheap
way of demonstrating the capabilities
of solar PV alongside LED bulbs for
lighting of public areas.
● Reduces municipality outgoings and
frees up revenue for funding other
schemes that could benefit the local
community
● There is no option for grid backup
without purchasing an inverter to
convert 220V AC to 12V DC
● The batteries would only last
approximately 550 cycles at close to
full capacity. After two years
replacements may need to be
considered.
Opportunities Threats
● The municipality can easily access
capital funding through the Canon
scheme to fund this scheme
● The high price of electricity will lead to
interest in alternative forms of
● ENOSA will charge for reconnection of
supply if the solar system fails.
● There is no confirmation as to how
ENOSA will react if there is reduced
electricity demand from grid sources in
Lobitos
93http://www.mrsolar.com/universal-power-12v-86ah-gel-battery/?page_context=category&facet
ed_search=0
94 http://www.led-cfl-lighthouse.com/page/1449301
95http://www.mrsolar.com/solartech-spm140p-s-f-140w-12v-solar-panel/?page_context=category
&faceted_search=0
generation from the municipality and
public of Lobitos
● The success or failure of the system
could be used for political purposes
which could affect other work planned
by EcoSwell
6.3.7 School- Use of solar to offset bills for the schools/for education
Application title Use of solar PV in the school
Stakeholder
group
Secondary school
Application description
This application is based on two factors:
1. to reduce electricity bills of the school through generating power using solar electricity,
2. to provide a practical example of solar PV that could be incorporated into the curriculum
to support education on electricity generation, renewable energy and wider sustainability
issues.
In addition to this, implementation of a PV system at the school would be a good way to introduce
the technology to the town of Lobitos as there are links from the school to all parts of the
community.
The secondary school has 55 12-18 year old students who are all from Lobitos. The schools
opening hours are from 7.30 till 1pm. There are 8 teachers in the secondary school with 6 paid for
by the Ministry for Education (national department) and 2 paid for by the municipality. The school
teaches sciences, technology and environmental classes (amongst other subjects). The school
running costs are covered by charges the parents a fee of 35 soles per child per year. This income
stream is unreliable as most parents do not pay it leading to issues regarding bill payments.
The secondary school, primary and nursery schools are all situated on the same plot with total
electricity used metered and charged as a single bill. There have been disputes over the amount
each institution should pay based on the number of pupils at each school and the activities that
are undertaken in each building (e.g. primary school has a kitchen with microwaves and a kettle).
The electricity bill is paid for solely by the parents charge. Last October the electricity was cut off
from grid electricity due to unpaid bills. This incurred a reconnection fee when outstanding
parent’s payments were collected. Details of the primary and nursery schools that are based at
the same site are not available as they could not be reached for an interview.
The secondary school has several appliances that utilise electricity but the main ones are: 13
computers with LCD monitors (see Photograph 20) and 3 flat screen TVs (see Photograph 17) that
are used in some lessons. They have a science lab with numerous dynamos and electric motors
(see Photograph 18).
Photograph 17: Example TV in a classroom
Photograph 18: Electrical teaching equipment
Photograph 19: Side of secondary school building with view of flat roof
Photograph 20: Computer room
Literature review
American School and University website published an article on the use of PV to offset running costs whilst as enriching the school curricula . The article highlights the added benefit of
96
providing tailored education for students who may wish to enter the growing green employment sector, something which has parallels with Lobitos. The suitability criteria of a school or educational facility for installation and operation of PVs systems has also been explored in the article. Topics for consideration include:
● Space. Do the facilities have unused and available land or well-oriented roofs with minimal obstructions?
● Assessment of Solar resources. For the geographical location of the proposed installation ● Electricity pricing and reliability.
96 http://asumag.com/energy/going-solar-green-schools
● Available rebates and subsidy. An example of a successful educational institution adopting PV to offset energy costs is the Pioneer Middle School in the USA. Aside from generating electricity the teachers have integrated the PV systems into their curriculum using the Web-based monitoring system used as part of the power purchase agreements (contracts between a third party owner of the PV system and the school). This allows the demonstration of the quantities of electricity provided by the system at any time as well as the variation in this generation. The district has seen significant savings on its utility bills, and the students are growing up with the awareness that their schools are doing something good for the environment. The Practical Action report ‘Schools and Safe and Healthy Housing. Practical Solutions for Rural and Semi-Urban Areas’ highlights the potential for PV for use in education in Peru (document translated from Spanish). The report highlights a number of uses for solar energy including use in schools for powering appliances, educational equipment (Audiovisual and multimedia) and for lighting. The report also highlights a number of projects that Practical Action have completed related to solar energy in Peru including:
● rural electrification schemes, ● Providing support to the District Municipalities to allocate budgets to finance
hydroelectric, photovoltaic systems, ● Providing resources for maintenance of equipment across 9 solar installations which have
been developed to allow access to Internet and use of ICT resources. These projects were fund by organisations such as: Lutheran World Relief, Christadelphian Meal-a-Day Fund of the Americas, Government of Aragón, Provincial de Zaragoza, the Spanish Agency for International Cooperation for Development (AECID) and the APC Embassy Program Japan. D:\Useful docs\Energy Schools, Practicle action (english)_files\Energy Schools, Practicle action
(english).htm
Outline design
Visual site survey and mode of operation The school is situated in Nuevo Lobitos in a secure compound. The 3 school buildings are on the same site with this primary and secondary schools consisting of 2 floor blocks (see Photograph 19). The kindergarten is a 1 story building at the back of the site. The roof of the secondary school building is flat whereas the primary school roof is pitched with one face orientated in a north easterly direction. If panels were roof mounted then there would be minimal shading. A rough load assessment was undertaken for the secondary school but access was not obtained to survey the kindergarten and primary school. Accordingly this application only relates to the secondary school loads but if carried forward to detailed design then assessment of other loads to form and integrated system for all loads would be appropriate. The system has been designed as a stand-alone system with the loads listed envisaged to be
attached via a separate circuit. This will diminish reliability on grid electricity while acting as an
educational tool to support lessons about energy and sustainability issues. There is scope for this
application be powered by a grid fall back system with either without or with a small scale battery
bank. The information required for this system setup would be broadly similar to the stand alone
design so a stand-alone system will be specified in this case with grid fall back option looked at in
more detail if this application is taken through to detailed design.
Figure 15: School site
Outline design The load that will be drawn by the computer towers will vary with the tasks that the computer is performing. An estimate of 150W has been calculated as an average of several brands of computer tower energy usage . The length of use has been estimated at 4 hours per day and
97
assumes that the computers will be turned off when not in use. The computer monitors have been estimated to be 19” and operating at 22W . The time in use
98
has been estimated at 4 hours to match the use of the computers. This assumes that the monitors are turned off when not in use.
97 http://www.letheonline.net/consumption.htm
98 http://energyusecalculator.com/electricity_lcdleddisplay.htm
The TVs have been estimated as 24” and have an associated power usage of 120W . The time in 99
use has been set very low to account for the fact that the 3 TVs will unlikely that all will be in use at the same time. Device Voltage
(V) Power (W)
Length of use (hours/day)
Number of items
Power use over 24 hours (Wh/day)
Computer tower 220 150 4 13 7800 Computer LCD monitor 19"
220 22 4 13 1144
Flat screen TV 24"
220 120 0.5 3 180
Table 27: Load profile for the secondary school
Outline design An inverter is required to run the equipment at grid supply conditions. If all loads were operating simultaneously then there would be a 2596W load on the inverter. In order to service this, the Power Inverter 3000W 12V Pure Sine Wave Inverter would be sufficient. The unit offers 85%
100
efficiency at full load which has been carried through to the battery assessment. The number of days of autonomy has been set to 1 as grid connection will be maintained to the secondary school building. If there is panel downtime or reduced levels of irradiance then 1 days contingency will be available before transferring loads back to the conventional grid supply. In addition it is likely that the loads will be in operation during the hours of daylight reducing the size requirements of the battery bank as electricity with be routed straight from the panel array to the loads (via the inverter) if sufficient irradiation is available. Temperature conversion data and depth of discharge have been taken from the MK 8G27 86Ah 12V Gel Battery . This is a Gel battery that at 75% depth of discharge is capable of providing 750
101
cycles. 7 battery units would be required for this system.
AC loads 9124 Wh/day 9124 Wh/day
Inverter efficiency 88% % 10368 Wh/day
DC loads 0 Wh/day 10368 Wh/day
Number of days of autonomy
1 days 10368 Wh
Temperature compensation 98% % 10580 Wh
Depth of discharge 75% % 14106 Wh
Voltage 24 V 588 Ah
Battery bank requirements: 0.59 kAh
99 http://energyusecalculator.com/electricity_lcdleddisplay.htm
100
http://www.aliexpress.com/store/product/Best-quality-3000w-3kw-DC-to-AC-Pure-Sine-Wave-12
V-110V-120V-60Hz-3000W-Power/216570_1255163485.html
101 http://www.mrsolar.com/content/pdf/MKBattery/8G27.pdf
Table 28: Battery bank requirements for secondary school loads
The shading efficiencies for this application have been set at 95% to due to the low probability of shading from other buildings. The 130W SolarTech SPM130P-S-F 130W 12V Solar Panel would
102
be an appropriate panel to use for this application with 21 units required to service the load and battery bank. Total solar resource required 9124 Wh/day
Battery efficiency 85% %
PV array efficiency 75% %
System efficiencies 64% %
Shading efficiencies 95% %
Overall efficiencies 61% %
PV system - efficiency losses 15065 Wh/day
Peak sun hours 5.50 Hours/day
PV system sized to available energy 2739 W
Table 29: Panel array assessment for secondary school loads
Outline cost estimates
Component Number of units Cost per unit
Total cost
Power Inverter 3000W 12V Pure Sine Wave Inverter
1 $390.00 103
$390.00
MK 8G27 86Ah 12V Gel Battery 7 $208.00 104
$1456.00 SolarTech SPM130P-S-F 130W 12V Solar Panel
21 $263.00 105
$5523.00
Total cost: $7369.00 Table 30: Indicative costs for the main pieces of equipment required for lighting of the football court
Estimated costs of the main equipment for this application is approximately $7369.00 not
including shipping, cables, mounting, charge controllers or maintenance.
Strengths Weaknesses
● Provides cost reduction for the schools
and may alleviate the financial
● Excess electricity cannot be fed back
into the grid so the school would be
unable to make money from the
102 http://www.mrsolar.com/content/pdf/Solartech/SPM130P-S-F.pdf
103http://www.aliexpress.com/item-img/Best-quality-3000w-3kw-DC-to-AC-Pure-Sine-Wave-12V-1
10V-120V-60Hz-3000W-Power/1255163485.html
104 http://www.mrsolar.com/mk-8g27-86ah-12v-gel-battery/
105http://www.mrsolar.com/solartech-spm130p-s-f-130w-12v-solar-panel/?page_context=categor
y&faceted_search=0
pressures that are currently being
experienced.
● The system could also act as a valuable
teaching aid that will allow the children
to understand how solar electricity
works and the potential benefits and
drawbacks of the technology. This
could lead to wider take up of the
technology throughout Lobitos.
electricity they generate. This means
that financing the installation of the
equipment may be challenging
●
Opportunities Threats
● There is a secure site compound
surrounding the school and space
where the panels could be placed.
● The distribution of the benefits of
reducing electricity bills through use of
solar electricity could lead to more
disagreements between the 3
academic institutions.
6.3.8 Municipality- Desalination of water to use in gardens/parks
Application title Solar desalination in order to produce water for communal gardening projects
Stakeholder
group
Municipal government
Application description
The municipality requested that an application to desalinate water for use on communal green spaces was investigated. During the time that the British Oil company was managing the Lobitos area there were many well managed parks and gardens (see appendix A). There is a lot of nostalgia for this era as well as strong political will to implement projects that will improve the appearance of the area. Communal green spaces are seen as central to this aspiration although there is large pressure on water resources throughout the Piura region. One solution would be to desalinate sea water for use in these gardens, fulfilling the community aims while not adding pressure onto existing water resources. There are two filter desalination plants in the area, in Talara and El Alto. The Talara desalination plant was constructed by the British oil company but when the military took over they decommissioned it as it was too expensive to run due to maintenance of filters and power requirements (see appendix A). The plant at El Alto was built recently by a municipality but the mayor overseeing the project was removed from office. The new mayor tried to run the plant but ran into constitutional issues as the municipality cannot take an income/profit from the public outside of current funding arrangements. This meant that the plant has been mothballed. This application investigates the possibility of constructing solar sill to desalinate water for use in gardening. The PV powered pumps will be scoped to feed the sills with sea water.
Photograph 21: Potential green area in front of the municipal palace
Photograph 22: View of potential area for solar sills
Figure Figure
Figure Figure
Literature review
Solar sills are a highly efficient and effective method of distilling brackish water, removing salts, microbes and nitrogen compounds. There are numerous examples of solar sills that use evaporation to desalinate water rather than electric pumps and filters to remover the salt. Solar sills also have the advantage of being a passive system with minimal maintenance. Practical Action has produced guidance on both irrigation systems and desalination techniques
106
offering advice on how to design a sill to efficiently create fresh water and how to use that 107
water to maximise impact.
106http://cdn1.practicalaction.org/m/i/53f3632d506849908ac16ff40a000075.pdf.
107http://practicalaction.org/media/preview/10523
An example of a distillation sill is described in Figure 16. The solar radiation enters the sill through the glass plate evaporating the clean water while impurities and salts are left behind. This pure water then condenses on the underside of the plate and is collected in the runoff channel. The brackish water would either be manually entered into the sill or a pump could be used. The Practical action guide suggest that the saline solution is kept to a depth of no more than 20mm to allow more efficient uses of solar energy to be converted into evaporation action.
Figure 16: Cross section of a solar sill
In order to maximise the operational efficiency of the solar sill, three elements should play into the design:
1. A high water temperature in the saline solution reservoir through maintain a shallow water level in the reservoir and ensuring low heat leakage through walls and floor
2. Maintaining a large temperature differential between the reservoir and the condensing surface (achieved through using a low heat absorption condensing surface and quick removal of condensed water through use of secondary air or water flow across the condensing surface).
3. Ensuring low levels of leakage of evaporated vapour from the sill. Glass is preferable for the condensing surface as plastics degrade after prolonged exposure to ultra violet light. Irrigation To ensure efficient use of limited fresh water resource, micro irrigation methods are recommended by Practical Action. Drip irrigation systems and pipe irrigation systems are both low cost, efficient methods of irrigation. Drip irrigation utilises a header tank to feed a network of pipes with small holes in to deliver water to plants and crops over time. Benefits of this system include reduced manual labour requirements with saving on watering time and reduced growth of weeds as the water can be specifically targeted in specific areas. DecRen Water Consult list the benefits of sub surface drip irrigation as:
108
● 50% reduction in plant watering requirements
108 http://www.dwc-water.com/technologies/irrigation/index.html
● Reduced soil compaction and aeration leading to less labour requirements ● Reduced soil erosion and water runoff ● Increases yield of agricultural products and seedlings
Pumps to supply the sill There are several potential pump and panel configurations that can supply the sill system. One of the most reliable is a stand-alone, direct power, submersible, brushless DC pump that only operates when the solar irradiance is sufficient to power the pump motor . This system is cheap,
109
reliable and maintenance free. A mounting point will be required to mount the inlet to ensure permanent submersion. The system does not require batteries and can feed water into a header tank which then supplies the sills. Practical Action has a technical guide to the different methods of operating a solar pump with the recommended system being a surface suction pump set . They warn that this type of application
110
is only suitable for low heads of less than 8m.
Outline design
Visual site survey operation There is a large degree of flexibility in the siting of the sill. The main requirements are for it to be close to a source of water (the sea) and be accessible by water truck so that the water generated can be transported to where it is required. The area of land in front of the ARPA building would be an appropriate location for construction of the sill infrastructure. The red area marked in red in Figure 17 measures 400m2 which should provide sufficient area to design an appropriate sill. This site is free from obstruction, is 110m from the sea but far enough to not be damaged or flooded by storms or high tides. The area is free from obstructions that would potentially shade the sill and is on flat ground so would not require extensive earthworks to construct. The pump system to supply water for the sill could be mounted on one of the pier legs allowing secure and consistent access to water for the system.
109 http://ilri.org/infoserv/Webpub/fulldocs/IWMI_IPMSmodules/Module_4.pdf
110 http://practicalaction.org/downloads/success/10552/lng:en
Figure 17: Potential area for locating desalination sills
In this application the PV pump system can be operated without use of a battery backup. This is due to the operational efficiency of pump and sill both being dictated by the solar irradiance (i.e. there would be no need to operate the pump at night as the sill will not be operating). There are many benefits to this:
1. The sills will not be over supplied with brackish water (although overflows will still be required)
2. the system costs will be significantly reduced as a battery bank will not be required 3. maintenance requirements will be reduced the main maintenance requirement being on
the pump
Design assessment for the solar sill The Practical Action report contains a formula for estimating the output of a solar sill as:
Q = LE G A* *
Where: daily output of distilled water (litres/day) Q =
overall efficiency E =
daily global solar irradiation (MJ/m²) G =
The latent heat of vaportisation of water 2.26 MJ/kg L = =
aperture area of the still ie, the plan areas for a simple basin still (m²) A =
As stated in section 4.5, the average solar irradiation in Lobitos is 5kWh/m2 which equates to 18.0MJ/m². The report states that an efficiency of approximately 30% should be expected. Therefore we can calculate an output per m2 as:
Q = 2.260.30 18 1* *
.39 litres/day per m of sill aperture Q = 2 2
Using the Practical Action drip irrigation case study, 60m2 area can be watered using a 20 litre water source that is filled twice a day (40 litres is required per day). Assuming two 30m2 gardens were serviced that would give a total water requirement of 40 litres per day. Using the value of Q above this would require an aperture area of:
0 A = Q * 4
.39 0 A = 2 * 4
6 m A = 9 2
This could comfortably be supplied by a sill measuring 10m by 10m. Load assessment Assuming 5 hours a day operation (based on figures in section 4.5) and water requirements of 40l per day the requirements of the pump are:
low in litres per hour f = 540
low in litres per hour f = 8
A suitable pump would be the LVM-114/12 Niagara 12V in line pump . This can be permanently
111
submerged and is suitable for marine applications. The pump is rated at 38W and can pump a maximum head on 10m. This pump can operate at a flow rate of 13l/min or 780l/hour. Trip switches and overflow pipes should be installed to ensure the sill is not overfilled. Device Voltage
(V) Power (W)
Length of use (hours/day)
Number of items
Power use over 24 hours (Wh/day)
LVM-114/12 Niagara 12V in line pump
12 38 1 1 38
Table 31: Load assessment to supply the desalination sill with brackish water
Outline design
111 http://www.windandsun.co.uk/products/Pumps/Low-Voltage-Pumps
This application is non-critical and the load requirements coincide with peak irradiance so can therefore be designed without battery backup. This will dramatically reduce costs and maintenance requirements. Total solar resource required 38 Wh/day
PV array efficiency 75% %
System efficiencies 75% %
Shading efficiencies 95% %
Overall efficiencies 71% %
PV system - efficiency losses 53 Wh/day
Peak sun hours 5.50 Hours/day
PV system sized to available energy 10 W Table 32: Panel array requirements for the pump to supply the desalination sill
The shading efficiencies for this application have been set at 95% to due to the low probability of shading from other buildings. The 10W SolarTech SPM010P-A 10W 12V Solar Panel would be an
112
appropriate panel to use for this application with only 1 unit required to service the load. Outline cost estimates
Component Number of units Cost per unit
Total cost
SolarTech SPM010P-A 10W 12V Solar Panel
1 $90 113
$90
LVM-114/12 Niagara 12V in line pump
1 $£21.04 114
$21.04
Clear Cast Perspex Acrylic (price per m2)
10 $49.27 115
$490.27
Ready mix concrete (price per m3) 30 $131.74 116
$3952.20 Total cost: $4553.51 Table 33: Indicative costs for the main pieces of equipment required for operating the desalination sill
Estimated costs of the main equipment for this application is approximately $4553.51 not including shipping, cables, mounting, fresh water tanks, hose or maintenance. Note that the cost
112 http://www.mrsolar.com/content/pdf/Solartech/SPM010P-A.pdf
113
http://www.mrsolar.com/solartech-spm010p-a-10w-12v-solar-panel/?page_context=category&fa
ceted_search=0
114 http://www.windandsun.co.uk/products/Pumps/Low-Voltage-Pumps
115 http://www.cutplasticsheeting.co.uk/clear-acrylic-sheeting/clear-cast-acrylic.html
116
http://www.lets-do-diy.com/Projects-and-advice/Concrete-work/Average-ready-mix-concrete-cos
t.aspx
of the acrylic screen and concrete are estimates and converted from Pounds to US Dollar on 11/06/2015 at an exchange rate of 1.55 US Dollars to 1 Pound.
Strengths Weaknesses
● The solution will fulfil the political and
community aims of implementing
gardens and green spaces in Lobitos
without placing additional pressure on
current sources of water.
● The design of the system is simple and
low cost. Maintenance is low and
replacement equipment is relatively
cheap.
● Security of the water and equipment
will be hard to maintain
● Efficient storage of the freshwater
would have to be included in the
design
Opportunities Threats
● The municipality already have access to
two bulk liquid carrying trucks
● The maintenance of the sill and
gardens would create jobs that could
be carried out by the local population.
● Pollution in seawater could still reside
after the desalination process leading
to contamination of bulk liquid
carrying trucks
● Coastal land is under great pressure
from Hostel owners and land bankers
so finding a suitable site for this
installation may be difficult
● Coastal erosion and careful positioning
of the installation and abstraction
points will be required to ensure that
environmental and social impacts are
minimised.
● There may be negative PR about using
government funds for non-essential
work
6.4.Applications not considered Data was collected and initial investigations were made to assess several applications that were
not carried forward to the outline design phase. The descriptions of these applications and the
reasons for not taking them forward are logged in Appendix A.
6.5.Discussion There are a number of suitable applications that can be serviced by solar PV systems in the Lobitos
area. These could potentially improve safety, efficiency, cost savings and improvement to the lives
of the community.
The cost of purchasing, augmenting and replacing batteries over the life of the systems that have
been investigated is generally the biggest expense and will therefore act as a barrier to making a
sound financial case for installing many of the systems specified. This is exacerbated by the fact
that no income will be received for excess electricity as export of into the grid is not permitted. For
this reason the applications have been specified generally as stand-alone (6.3.1, 6.3.2, 6.3.3, 6.3.4,
6.3.5, 6.3.6, 6.3.7) with one exception (6.3.8) which operates purely off power produces by the PV
array. Investigation of grid fall back designs will be undertaken in the detailed design to see haw
costs may be affected as well as optimising the system to reduce battery bank costs.
The depth of discharge is also a factor in optimising the battery bank with lower depth of
discharge elongating battery bank life but increasing the upfront capital costs. Investigation of
where the best depth of discharge point is to supply value for money will be undertaken in the
detailed design.
6.6.Recommendation for application to take forward to detailed design The full list of applications and costs are included in table 34 below with estimated costs included.
Number Application Cost estimate 6.3.1 Winch for fishing vessel haul out $11,726.50 6.3.2 Jib crane/winch for vessel unloading $9847.43 6.3.3 Lighting of the fishing quay $6641.00 6.3.4 Pumping water for ARPA production building water tower $458.04 6.3.5 Use of solar to offset electricity bills for residents or small
businesses $6256.75
6.3.6 Lighting of the community football courts $2876.00 6.3.7 Use of solar PV in the school $7369.00 6.3.8 Solar desalination in order to produce water for communal
gardening projects $4553.51
Table 34: List of applications and estimated costs
The winch for vessel haul out (6.3.1) utilises 14 150Ah batteries discharging at 1C and then
recharging over a long period. It is estimated that the batteries augmented or replaced after a
year meaning that the cost estimate for this project is lower than a 10 year life span. At this rapid
a discharge the batteries will be under a lot of strain and may cause failure. In addition to supply
the required wattage, very thick cables are required and risk of injury may be high. From a user
perspective there are issues around the need for the equipment, safety concerns and reservations
regarding the reliability of solar PV equipment after the lighting system failed. These would have
to be overcome to gain acceptance of the system but there are significant costs and challenges
associated with doing this.
The jib crane/winch application (6.3.2) is similar in that this would be an application pushed on the
user rather than being a need requested. The same issue about full life cost due to battery
replacements, augmentations are true as 6.3.1 although not to the same scale. This would be
useful application to design a solution for as there could be wide applicability across Peru and
other fishing quays around the world. However the fact that there is not a ready-made system
already means that there is minimal demand or the challenges of developing the system are too
great.
The quay lighting (6.3.3) provides a challenge that is well within the capabilities of a solar system.
The load is predictable and will save the ARPA money. There is also a wide applicability for the
system around Lobitos for street and security lighting projects. There are issues with perception
due to the previous failure of technology however with training and technical support the system
should operate comfortably for 10 years if not longer. These points are also applicable to the
lighting of the football court (6.3.6).
The water pumping application (6.3.4) presents a challenge due to the discharge of a battery over
a short intermittent period of time. This is exacerbated by the pump operation on single phase AC
significantly restricting the choice and size of inverters available to use in the application. There
are several options which would make the system easier to design such as changing the pump to a
12V DC unit or holding water in a tank at the bottom of the tower and using a pump directly linked
to the panels to pump water to the upper holding tank to generate the head pressure required.
Both of these solutions would add to the initial capital costs but would pay back and have a longer
operational lifetime that the stand alone system option.
Both the residents/small businesses (6.3.5) and school (6.3.7) examples are not particularly suited
to using stand-alone PV systems. Large battery banks and inverters are required in both examples
to allow power to be supplied at a suitable voltage and AC. In addition, the loads in both
applications are relatively critical and so an over specified system is required in stand-alone mode.
A grid fall back option would be a more appropriate design in both these cases reducing the
requirement for a battery bank and associated capital costs. This would increase the on-going cost
in comparison to a stand-alone system as some electricity will still be required from the grid.
There is currently no policy from ENOSA as to if a grid fall back design is allowable however all the
modifications could be made on the customer side of the meter to ensure that there are no issues
with this.
The desalination application (6.3.8) is an elegant solution that minimises moving parts and
maintenance. The application is not a particularly high priority with other applications offering the
community a direct monetary, safety or physical benefit. This design could be presented to the
Municipality so that they could take it forward using their own funds.
Considering the points above application 6.3.3 to use solar PV to light the fishing quay will be
taken forward to detailed design. Clarification on Enosa policy for solar systems on the customer
side and associated billing should be undertaken to allow development of 6.3.5 and 6.3.7 in the
future as this applications would work significantly better in tandem with the grid than as
stand-alone systems.
APPENDICES
A. Applications not carried forward
Application name Application description Reasons for not carrying forward
Electric fish drying facility There are currently no fish drying or cold storage facilities around the Lobitos fish quay. The current practice is to sell the fish that are landed straight to distributers who chill, transport, process and sell it in the nearby town of Talara. Some fish is retained for personal consumption. The interview also highlighted that the fleet is currently susceptible to large fluctuations in catch and therefore price as all catch has to be sold immediately after landing
There are no ready-made systems or case studies that can be drawn on to prove the concept Maintenance and repair costs of equipment should be kept to a minimum as funds for repair would be taken out of fishermen’s increased profits There would have to be strong cooperation between the fishermen to allow balancing of supply of fish with demand and pricing There is no current market for dried fish from Lobitos. This means that the idea would have to be sold to fish distributers
Fishermen-powered freezing of fish/ice production
There are currently no ice making or refrigeration facilities either on fishing vessels or on the quayside at Lobitos. The fishermen rely on selling fresh fish straight to distributers on the quayside that have refrigerated trucks to transport the produce to Talara for processing and sale. Ice machines or other refrigeration facilities were identified as being a valuable asset for the fishermen of Lobitos for the rare occasions that the distributers cannot make it to the quay in good time.
Maintenance and repair costs of equipment should be kept to a minimum as funds for repair would be taken out of fishermen’s increased profits The processing plan was left unused due to diminishing fish stocks and a similar issue may occur here Too power hungry
Hostel owners- use of solar electricity to offset running costs
These interviews that there is a potential demand for solar energy to offset energy costs of hostels in the Lobitos area. The main barriers currently are cost of installation and knowledge of the capabilities or operation of solar systems. The application could involve setting up a pilot installation on one of the hostels to demonstrate the operation and potential savings to hostel owners of implementing a solar system. This could initially be for running one appliance like a fridge to demonstrate the technology thus avoiding the complete removal of costly grid connections.
This application would be unlikely to get funding in the form of a grant as the applications main purpose would be to improve profits of the hostel owners The technology demonstration ill not be available to local people in Lobitos and will
Municipality- use of solar on municipal palace (office)
The municipality are interested in the possibility of fitting municipal buildings with solar panels to lower their ongoing revenue costs. The largest municipal building is the municipal palace situated in New Lobitos which houses all administrative staff, managers and the mayor’s office. In total are 45 people work in this building with electricity use mainly coming from the use of computers and IT equipment (no servers). Receipts The benefit of this application would be to lower ongoing running cost of the municipality allowing this to be spent in other areas that could employ more of the local community through the cleaning and security schemes that are currently ongoing. There would also be the added benefit of introducing
Excess electricity cannot be fed back into the grid on the micro scale currently which means that the solar systems will have to be stand alone with grid backup This application is not the best in terms of providing an example application for use by others in Lobitos as the levels and types of demand are unique (i.e. high and stable levels of demand though use of IT equipment). Loading assesment
solar technology to the people of Lobitos and demonstrate its potential in the area.
The use of solar electricity to pump sewage to oxygenation ponds
As the oxygenation ponds are outside of the town of Lobitos, a series of 3 pumps are required to transfer sewage. The pumps that were procured under the initial funding were tri phase electric pumps but the current grid connection in Lobitos is only monophase. New pumps are on order that will operate on monophase. Two of the pumps are located close to transmission wires but one site would need an extension to the grid in order to operate. This location could be powered by electricity produced by solar energy.
There would be no backup for the solar system so reliability is essential There is no fixed demand so the solar system would have to be over specified to allow for variations in supply and demand The demand from the pump could be extremely high and out of the capabilities of a solar system
Municipality/bill payers- solar street lighting
Large parts of Lobitos are unlit at night which is perceived to be a security risk. The mayor highlighted this in the initial meeting as being one of the areas where he would like us to investigate how solar electricity could help. The current light systems run on grid electricity and utilise 80 watt bulbs which run during the hours of darkness. The operation of these lights is controlled by light sensors. A new system utilising more up to date technology could be installed to allow the use of the full lighting system. This project may also involve changing the bulbs in the lamps to energy saving bulbs or LEDs.
Any new lighting systems would have no grid back up meaning that the system would have to be reliable The equipment would have to be secured to avoid damage, theft or illegal siphoning or electricity.
Health centre- solar for health centre to enable setting up of a laboratory
This application would involve integrating solar panels onto the health centre building to power laboratory equipment. This system would have to either have grid backup or be
There is no real demand currently to upgrade the health post either from the community or the Ministry of Health
designed to power non-essential equipment. There are no details about what equipment will be required so the literature review would need to inform requirements based on similar case studies.
There is no clear specifications of the equipment required to set up a laboratory function meaning that it would be difficult to create a specification and cost for implementing a solar system