Photovoltaic power station
A photovoltaic power station, also known as a solar park, is a large-scale photovoltaic system (PV) designed for the supply of merchant power into the electricity grid. They are differentiated from most building-mounted and other decentralised solar power applications because they supply power at the utility level, rather than to a local user or users. They are sometimes also referred to as solar farms or solar ranches, especially when sited in agricultural areas. The generic expression utility-scale solar is sometimes used to describe this type of project.
The power conversion source is via photovoltaic modules that convert light directly to electricity. This differs from the other large-scale solar generation technology, concentrated solar power, which uses heat to drive a variety of conventional generator systems. Both approaches have their own advantages and disadvantages, but to date, for a variety of reasons, the PV-based systems have seen much wider use in the field. As of 2013[update], PV systems outnumber concentrators by about 30 to 1.
Photovoltaic power stations are typically rated in terms of the DC peak capacity of the solar arrays, in megawatt-peak (MWp), or of the nominal maximum AC output in megawatts (MW) or mega volt-amperes (MVA). Most solar parks are developed at a scale of at least 1 MWp. The largest operating photovoltaic power stations have capacities of hundreds of MWp; projects up to 1 GWp are planned. The cumulative worldwide capacity of plants of 4 MWAC and over as at the end of 2013 was reported to be 21 GW or 15 percent of global total.
Most of the existing large-scale photovoltaic power stations are owned and operated by independent power producers, but the involvement of community- and utility-owned projects is increasing. To date, almost all have been supported at least in part by regulatory incentives such as feed-in tariffs or tax credits, but capital costs have fallen significantly in the last decade and are expected to progressively reach grid parity, when external incentives may no longer be required.
- 1 History
- 2 Siting and land use
- 3 Technology
- 4 The business of developing solar parks
- 5 Economics and Finance
- 5.1 Grid parity
- 5.2 Incentive mechanisms
- 5.3 Financial performance
- 6 Geography
- 7 See also
- 8 References
- 9 External links
The first 1 MWp solar park was built by Arco Solar at Lugo near Hesperia, California at the end of 1982, followed in 1984 by a 5.2 MWp installation in Carrizo Plain. Both have since been decommissioned, though Carrizo Plain is the site for several large plants now being constructed or planned. The next stage followed the 2004 revisions to the feed-in tariffs in Germany when a substantial volume of solar parks were constructed.
Several hundred installations over 1 MWp have been since been installed in Germany, of which more than 50 are over 10 MWp. With its introduction of feed-in tariffs in 2008, Spain became briefly the largest market, with some 60 solar parks over 10 MW, but these incentives have since been withdrawn. The USA, China India, France, Canada, and Italy, amongst others, have also become major markets as shown on the list of photovoltaic power stations.
The largest solar parks currently operating have capacities between 200 and 300 MWp. The largest sites under construction have capacities of hundreds of MWp and projects at a scale of 1 GWp are being planned. Some solar parks that are notable in the global or regional context are listed in this article.
Siting and land use
The land area required for solar parks varies depending on the location, and on the efficiency of the solar modules, the slope of the site and the type of mounting used. Fixed tilt solar arrays using typical modules of about 15% efficiency on horizontal sites, need about 1 hectare/MW in the tropics and this figure rises to over 2 hectares in northern Europe.
Because of the longer shadow the array casts when tilted at a steeper angle, this area is typically about 10% higher for an adjustable tilt array or a single axis tracker, and 20% higher for a 2-axis tracker, though these figures will vary depending on the latitude and topography.
The best locations for solar parks in terms of land use are held to be brown field sites, or where there is no other valuable land use. Even in cultivated areas, a significant proportion of the site of a solar farm can also be devoted to other productive uses, such as grazing or biodiversity.
In some cases several different solar power stations, with separate owners and contractors, are developed on adjacent sites. This can offer the advantage of the projects sharing the cost and risks of project infrastructure such as grid connections and planning approval. Solar farms can also be co-located with wind farms. Sometimes the title 'solar park' is used, rather than an individual solar power station.
Some examples of such solar clusters are the Charanka Solar Park, where there are 17 different generation projects; Neuhardenberg, with eleven plants, and the Golmud solar parks with total reported capacity over 500MW. An extreme example is calling all of the solar farms in the Gujarat state of India a single solar park, the Gujarat Solar Park.
Most Solar parks are ground mounted PV systems, also known as free-field solar power plants. They can either be fixed tilt or use a single axis or dual axis solar tracker. While tracking improves the overall performance, it also increases the system's installation and maintenance cost. A solar inverter converts the array's power output from DC to AC, and connection to the utility grid is made through a high voltage, three phase step up transformer of typically 10 kV and above.
Solar array arrangements
The solar arrays are the subsystems which convert incoming light into electrical energy. They comprise a multitude of solar modules, mounted on support structures and interconnected to deliver a power output to electronic power conditioning subsystems.
A minority of utility-scale solar parks are configured on buildings and so use building-mounted solar arrays. The majority are 'free field' systems using ground-mounted structures, usually of one of the following types:
Many projects use mounting structures where the solar modules are mounted at a fixed inclination calculated to provide the optimum annual output profile. The modules are normally oriented towards the Equator, at a tilt angle slightly less than the latitude of the site. In some cases, depending on local climatic, topographical or electricity pricing regimes, different tilt angles can be used, or the arrays might be offset from the normal East-West axis to favour morning or evening output.
A variant on this design is the use of arrays, whose tilt angle can be adjusted twice or four times annually to optimise seasonal output. They also require more land area to reduce internal shading at the steeper winter tilt angle. Because the increased output is typically only a few percent, it seldom justifies the increased cost and complexity of this design.
Dual axis trackers
To maximise the intensity of incoming direct radiation, solar panels should be orientated normal to the sun's rays. To achieve this, arrays can be designed using two-axis trackers, capable of tracking the sun in its daily orbit across the sky, and as its elevation changes throughout the year.
These arrays need to be spaced out to reduce inter-shading as the sun moves and the array orientations change, so need more land area. They also require more complex mechanisms to maintain the array surface at the required angle. The increased output can be of the order of 30% in locations with high levels of direct radiation, but the increase is lower in temperate climates or those with more significant diffuse radiation, due to overcast conditions. For this reason, dual axis trackers are most commonly used in subtropical regions, and were first deployed at utility scale at the Lugo plant.
Single axis trackers
A third approach achieves some of the output benefits of tracking, with a lesser penalty in terms of land area, capital and operating cost. This involves tracking the sun in one dimension - in its daily journey across the sky - but not adjusting for the seasons. The angle of the axis is normally horizontal, though some, such as the solar park at Nellis Airforce Base, which have a 20° tilt, incline the axis towards the equator in a north-south orientation - effectively a hybrid between tracking and fixed tilt.
Solar panels produce direct current (DC) electricity, so solar parks need conversion equipment to convert this to alternating current (AC), which is the form transmitted by the electricity grid. This conversion is done by inverters. To maximise their efficiency, solar power plants also incorporate maximum power point trackers, either within the inverters or as separate units. These devices keep each solar array string close to its peak power point.
There are two primary alternatives for configuring this conversion equipment; centralised and string inverters, although in some cases individual, or micro-inverters are used. Single inverters allows optimizing the output of each panel, and multiple inverters increases the reliability by limiting the loss of output when an inverter fails.
These units have relatively high capacity, typically of the order of 1 MW, so they condition that the output of a substantial block of solar arrays, up to perhaps 2 hectares (4.9 acres) in area. Solar parks using centralised inverters are often configured in discrete rectangular blocks, with the related inverter in one corner, or the centre of the block.
String inverters are substantially lower in capacity, of the order of 10 kW, and condition the output of a single array string. This is normally a whole, or part of, a row of solar arrays within the overall plant. String inverters can enhance the efficiency of solar parks, where different parts of the array are experiencing different levels of insolation, for example where arranged at different orientations, or closely packed to minimise site area.
The system inverters typically provide power output at voltages of the order of 480 VAC. Electricity grids operate at much higher voltages of the order of tens or hundreds of thousands of volts, so transformers are incorporated to deliver the required output to the grid. Due to the long lead time, the Long Island Solar Farm chose to keep a spare transformer onsite, as transformer failure would have kept the solar farm offline for a long period. Transformers typically have a life of 25 to 75 years, and normally do not require replacement during the life of a photovoltaic power station.
The performance of a solar park is a function of the climatic conditions, the equipment used and the system configuration. The primary energy input is the global light irradiance in the plane of the solar arrays, and this in turn is a combination of the direct and the diffuse radiation.
There will be losses between the DC output of the solar modules and the AC power delivered to the grid, due to a wide range of factors such as light absorption losses, mismatch, cable voltage drop, conversion efficiencies, and other parasitic losses. A parameter called the 'performance ratio' has been developed to evaluate the total value of these losses. The performance ratio gives a measure of the output AC power delivered as a proportion of the total DC power which the solar modules should be able to deliver under the ambient climatic conditions. In modern solar parks the performance ratio should typically be in excess of 80%.
Early photovoltaic systems output decreased as much as 10%/year, but as of 2010 the median degradation rate was 0.5%/year, with modules made after 2000 having a significantly lower degradation rate, so that a system would lose only 12% of its output performance in 25 years. A system using modules which degrade 4%/year will lose 64% of its output during the same period. Many panel makers offer a performance guarantee, typically 90% in ten years and 80% over 25 years. The output of all panels is typically warranteed at plus or minus 3% during the first year of operation.
The business of developing solar parks
Solar power plants are developed to deliver merchant electricity into the grid as an alternative to other renewable, fossil or nuclear generating stations.
Some of these power producers develop their own portfolio of power plants, but most solar parks are initially designed and constructed by specialist project developers. Typically the developer will plan the project, obtain planning and connection consents, and arrange financing for the capital required. The actual construction work is normally contracted to one or more EPC (engineering, procurement and construction) contractors.
Major milestones in the development of a new photovoltaic power plant are planning consent, grid connection approval, financial close, construction, connection and commissioning. At each stage in the process, the developer will be able to update estimates of the anticipated performance and costs of the plant and the financial returns it should be able to deliver.
Photovoltaic power stations occupy at least one hectare for each megawatt of rated output, so require a substantial land area; which is subject to planning approval. The chances of obtaining consent, and the related time, cost and conditions, varying from jurisdiction to jurisdiction and location to location. Many planning approvals will also apply conditions on the treatment of the site after the station has been decommissioned in the future. A professional health, safety and environment assessment is usually undertaken during the design of a PV power station in order to ensure the facility is designed and planned in accordance with all HSE regulations.
The availability, locality and capacity of the connection to the grid is a major consideration in planning a new solar park, and can be a significant contributor to the cost.
Most stations are sited within a few kilometres of a suitable grid connection point. This network needs to be capable of absorbing the output of the solar park when operating at its maximum capacity. The project developer will normally have to absorb the cost of providing power lines to this point and making the connection; in addition often to any costs associated with upgrading the grid, so it can accommodate the output from the plant.
Operation and maintenance
Before the commissioning phase, plants undergo a final installation inspection in order to ensure that the PV power station has been installed and connected in-line with all requirements. Once the solar park has been commissioned, the owner usually enters into a contract with a suitable counterparty to undertake operation and maintenance (O&M). In many cases this may be fulfilled by the original EPC contractor.
Solar plants' reliable solid-state systems require minimal maintenance, compared to rotating machinery for example. A major aspect of the O&M contract will be continuous monitoring of the performance of the plant and all of its primary subsystems, which is normally undertaken remotely. This enables performance to be compared with the anticipated output under the climatic conditions actually experienced. It also provides data to enable the scheduling of both rectification and preventative maintenance. A small number of large solar farms use a separate inverter or maximizer for each solar panel, which provide individual performance data that can be monitored. For other solar farms, thermal imaging is a tool that is used to identify non-performing panels for replacement.
A solar park's income derives from the sales of electricity to the grid, and so its output is metered in real-time with readings of its energy output provided, typically on a half hourly basis, for balancing and settlement within the electricity market.
Income is affected by the reliability of equipment within the plant and also by the availability of the grid network to which it is exporting. Some connection contracts allow the transmission system operator to constrain the output of a solar park, for example at times of low demand or high availability of other generators. Some countries make statutory provision for priority access to the grid for renewable generators, such as that under the European Renewable Energy Directive.
Economics and Finance
In recent years, PV technology has improved its electricity generating efficiency, reduced the installation cost per watt as well as its energy payback time (EPBT), and has reached grid parity in at least 19 different markets by 2014. Photovoltaics is increasingly becoming a viable source of mainstream power. However, prices for PV systems show strong regional variations, much more than solar cells and panels, which tend to be global commodities. In 2013, utility-scale system prices in highly penetrated markets such as China and Germany were significantly lower ($1.40/W) than in the United States ($3.30/W). The IEA explains these discrepancies due to differences in "soft costs", which include customer acquisition, permitting, inspection and interconnection, installation labor and financing costs.:14
|For utility-scale PV systems in 2013:15|
Solar generating stations have become progressively cheaper in recent years, and this trend is expected to continue. Meanwhile, traditional electricity generation is becoming progressively more expensive. These trends are expected to lead to a crossover point when the levelised cost of energy from solar parks, historically more expensive, matches the cost of traditional electricity generation. This point is commonly referred to as grid parity.
For merchant solar power stations, where the electricity is being sold into the electricity transmission network, the levelised cost of solar energy will need to match the wholesale electricity price. This point is sometimes called 'wholesale grid parity' or 'busbar parity'.
Some photovoltaic systems, such as rooftop installations, can supply power directly to an electricity user. In these cases, the installation can be competitive when the output cost matches the price at which the user pays for his electricity consumption. This situation is sometimes called 'retail grid parity', 'socket parity' or 'dynamic grid parity'. Research carried out by UN-Energy in 2012 suggests areas of sunny countries with high electricity prices, such as Italy, Spain and Australia, and areas using diesel generators, have reached retail grid parity.
Because the point of grid parity has not yet been reached in many parts of the world, solar generating stations need some form of financial incentive to compete for the supply of electricity. Many legislatures around the world have introduced such incentives to support the deployment of solar power stations.
Feed in tariffs are designated prices which must be paid by utility companies for each kilowatt hour of renewable electricity produced by qualifying generators and fed into the grid. These tariffs normally represent a premium on wholesale electricity prices and offer a guaranteed revenue stream to help the power producer finance the project.
Renewable portfolio standards and supplier obligations
These standards are obligations on utility companies to source a proportion of their electricity from renewable generators. In most cases, they do not prescribe which technology should be used and the utility is free to select the most appropriate renewable sources.
There are some exceptions where solar technologies are allocated a proportion of the RPS in what is sometimes referred to as a 'solar set aside'.
Loan guarantees and other capital incentives
Some countries and states adopt less targeted financial incentives, available for a wide range of infrastructure investment, such as the US Department of Energy loan guarantee scheme, which stimulated a number of investments in the solar power plant in 2010 and 2011.
Tax credits and other fiscal incentives
Another form of indirect incentive which has been used to stimulate investment in solar power plant was tax credits available to investors. In some cases the credits were linked to the energy produced by the installations, such as the Production Tax Credits. In other cases the credits were related to the capital investment such as the Investment Tax Credits
International, national and regional programmes
In addition to free market commercial incentives, some countries and regions have specific programs to support the deployment of solar energy installations.
The European Union's Renewables Directive sets targets for increasing levels of deployment of renewable energy in all member states. Each has been required to develop a National Renewable Energy Action Plan showing how these targets would be met, and many of these have specific support measures for solar energy deployment. The directive also allows states to develop projects outside their national boundaries, and this may lead to bilateral programs such as the Helios project.
Additionally many other countries have specific solar energy development programmes. Some examples are India's JNNSM, the Flagship Program in Australia, and similar projects in South Africa and Israel.
The financial performance of the solar power plant is a function of its income and its costs.
The electrical output of a solar park will be related to the solar radiation, the capacity of the plant and its performance ratio. The income derived from this electrical output will come primarily from the sale of the electricity, and any incentive payments such as those under Feed-in Tariffs or other support mechanisms.
The dominant costs of solar power plants are the capital cost, and therefore any associated financing and depreciation. Though operating costs are typically relatively low, especially as no fuel is required, most operators will want to ensure that adequate operation and maintenance cover is available to maximise the availability of the plant and thereby optimise the income to cost ratio.
The first places to reach grid parity were those with high traditional electricity prices and high levels of solar radiation. Currently, more capacity is being installed in the rooftop than in the utility-scale segment. However, the worldwide distribution of solar parks is expected to change as different regions achieve grid parity. This transition also includes a shift from rooftop towards utility-scale plants, since the focus of new PV deployment has changed from Europe towards the Sunbelt markets where ground-mounted PV systems are favored.:43
Because of the economic background, large-scale systems are presently distributed where the support regimes have been the most consistent, or the most advantageous. Total capacity of worldwide PV plants above 4 MWAC was assessed by Wiki-Solar as 21 GW in c. 1,500 installations at the end of 2013 and represents about 15 percent of total global PV capacity of 139 GW.:17 The countries which had the most capacity, in descending order, were the United States, China, Germany, India, United Kingdom, Spain, Italy, Canada and South Africa. Activities in the key markets are reviewed individually below.
China was reported in early 2013 to have overtaken Germany as the nation with the most utility-scale solar capacity. Much of this has been supported by the Clean Development Mechanism. The distribution of power plants around the country is quite broad, with the highest concentration in the Gobi desert and connected to the Northwest China Power Grid.
The first multi-megawatt plant in Europe was the 4.2 MW community-owned project at Hemau, commissioned in 2003. But it was the revisions to the German feed-in tariffs in 2004, which gave the strongest impetus to the establishment of utility-scale solar power plants. The first to be completed under this programme was the Leipziger Land solar park developed by Geosol. Several dozen plants were built between 2004 and 2011, several of which were at the time the largest in the world. The EEG, the law which establishes Germany’s feed-in tariffs, provides the legislative basis not just for the compensation levels, but other regulatory factors, such as priority access to the grid. The law was amended in 2010 to restrict the use of agricultural land, since which time most solar parks have been built on so-called ‘development land’, such as former military sites. Partly for this reason, the geographic distribution of photovoltaic power plants in Germany is biased towards the former Eastern Germany. As of February 2012, Germany had 1.1 million photovoltaic power plants (most are small kW roof mounted).
India has been rising up the leading nations for the installation of utility-scale solar capacity. The Charanka Solar Park in Gujarat was opened officially in April 2012 and was at the time the largest group of solar power plants in the world. Geographically the majority of the stations are located in Gujarat and Maharashtra. Rajasthan has unsuccessfully been attempting to attract solar development. It and Gujarat share the Thar Desert, along with Pakistan.
The majority of the deployment of solar power stations in Spain to date occurred during the boom market of 2007-8. The stations are well distributed around the country, with some concentration in Extremadura, Castile-La Mancha and Murcia.
The introduction of Feed-in tariffs in the United Kingdom in 2010 stimulated the first wave of utility-scale projects, with c. 20 plants being completed before tariffs were reduced on 1 August 2011 following the 'Fast Track Review'. A second wave of installations was undertaken under the UK's Renewables Obligation, with the total number of plants connected by the end of March 2013 reaching 86. This is reported to have made the UK Europe's best market in the first quarter of 2013.
UK projects were originally concentrated in the South West, but have more recently spread across the South of England and into East Anglia and the Midlands. The first solar park in Wales came on stream in 2011 at Rhosygilwen, near Cilgerran, Pembrokeshire. As of June 2014 there were 18 schemes generating more than 5 MW and 34 in planning or construction in Wales.
The US deployment of photovoltaic power stations is largely concentrated in South Western States. The Renewable Portfolio Standards in California and surrounding states provide a particular incentive. The volume of projects under construction in early 2013 has led to the forecast that the US will become the leading market.
Noteworthy solar parks
The following solar parks were, at the time they became operational, the largest in the world or their continent, or are notable for the reasons given:
|Lugo||USA||1 MW||Dec 1982||First MW plant|
|Carrisa Plain||USA||5.6 MW||Dec 1985||World’s largest|
|Hemau||Germany||4.0 MW||Apr 2003||Europe’s largest; community owned|
|Leipziger Land||Germany||4.2 MW||Aug 2004||Europe’s largest; first under FITs|
|Pocking||Germany||22 MW||Apr 2006||World's and Europe's largest|
|Nellis Airforce Base, Nevada||USA||14 MW||Dec 2007||America's largest|
|Olmedilla||Spain||60 MW||Jul 2008||World's and Europe's largest|
|Sinan||Korea||24 MW||Aug 2008||Asia's largest|
|Waldpolenz, Saxony||Germany||40 MW||Dec 2008||World's largest thin film plant. Extended to 52 MW in 2011|
|DeSoto, Florida||USA||25 MW||Oct 2009||America's largest|
|La Roseraye||Reunion||11 MW||Apr 2010||Africa's first 10 MW+ plant|
|Sarnia, Ontario||Canada||97 MW (80 MWAC)||Sep 2010||World's largest|
|Golmud, Qinghai,||China||200 MW||Oct 2011||World's largest|
|Finow Tower||Germany||85 MW||Dec 2011||Extension takes it to Europe's largest|
|Lopburi||Thailand||73 MW||Dec 2011||Asia's largest (outside China)|
|Perovo, Crimea||Ukraine||100 MW||Dec 2011||Becomes Europe's largest|
|Charanka, Gujarat||India||221 MW||Apr 2012||Asia's largest solar park|
|Agua Caliente, Arizona||USA||To be: 290 MWAC||Jul 2012||Reaches 200 MW (AC) in July 2012 to become world's largest solar park|
|Neuhardenberg, Brandenburg||Germany||145 MW||Sep 2012||Becomes Europe's largest solar cluster|
|Greenhough River, Western Australia,||Australia||10 MW||Oct 2012||Australasia's first 10 MW+ plant|
|Majes and Reparticion||Peru||20 MW||Oct 2012||First utility-scale plants in South America|
|Westmill Solar Park, Oxfordshire||United Kingdom||5 MW||Oct 2012||Acquired by Westmill Solar Co-operative to become world's largest community-owned solar power station|
|San Miguel Power, Colorado||USA||1.1 MW||Dec 2012||Biggest community-owned plant in USA|
|Sheikh Zayed, Nouakchott||Mauritania||15 MW||Apr 2013||Largest solar power plant in Africa|
|Topaz, California||USA||To be: 500 MWAC||2013||Construction started 2011/12. First 35 MWAC connected in April 2013.|
Solar power plants under development are not included here, but may be on this list.
- Wolfe, Philip. "Capacity rating for solar generating stations". Wiki-Solar. Retrieved 22 August 2013.
- Arnett, J.C. and others; Schaffer, L. A.; Rumberg, J. P.; Tolbert, R. E. L. (1984). "Design, installation and performance of the ARCO Solar one-megawatt power plant". Proceedings of the Fifth International Conference, Athens, Greece (EC Photovoltaic Solar Energy Conference): 314. Bibcode:1984pvse.conf..314A.
- Wenger, H.J. and others. "Decline of the Carrisa Plains PV power plant". Photovoltaic Specialists Conference, 1991., Conference Record of the Twenty Second IEEE. IEEE. Retrieved 13 April 2013.
- "Topaz Solar Farm". First Solar. Retrieved 2 March 2013.
- "The Renewable Energy Sources Act". Bundesgesetzblatt 2004 I No. 40. Bundesumweltministerium(BMU). 21 July 2004. Retrieved 13 April 2013.
- "Top 10 Solar PV power plants". SolarPlaza. Retrieved 22 April 2013. Retrieved 13 April 2013
- "Solar parks map - Germany". Wiki-Solar. Retrieved 13 April 2013.
- "Solar parks map - Spain". Wiki-Solar. Retrieved 13 April 2013.
- "An Early Focus on Solar". National Geographic. Retrieved 22 April 2013. Retrieved 13 April 2013
- "Solar parks map - USA". Wiki-Solar. Retrieved 13 April 2013.
- "Solar parks map - China". Wiki-Solar. Retrieved 13 April 2013.
- "Solar parks map - India". Wiki-Solar. Retrieved 13 April 2013.
- "Solar parks map - France". Wiki-Solar. Retrieved 13 April 2013.
- "Solar parks map - Canada". Wiki-Solar. Retrieved 13 April 2013.
- "Solar parks map - Italy". Wiki-Solar. Retrieved 13 April 2013.
- "Large-Scale Photovoltaic Power Plants". PV Resources. Retrieved 22 April 2013. Retrieved 13 April 2013
- Olson, Syanne (10 January 2012). "Dubai readies for 1,000MW Solar Park". PV-Tech. Retrieved 21 February 2012.
- "MX Group Spa signs a 1.75 Billion Euros agreement for the construction in Serbia of the largest solar park in the world". Retrieved 6 March 2012.
- "Statistics about selected locations for utility-scale solar parks". Wiki-Solar. Retrieved 13 April 2013.
- Joshi, Amruta. "Estimating per unit area energy output from solar PV modules". National Centre for Photovoltaic Research and Education. Retrieved 5 March 2013.
- "Screening Sites for Solar PV Potential". Solar Decision Tree. US Environmental Protection Agency. Retrieved 5 March 2013.
- "An overview of PV panels". SolarJuice. Retrieved 5 March 2013.
- "Calculating Inter-Row Spacing". Technical Questions & Answers. Solar Pro Magazine. Retrieved 5 March 2013.
- Wolfe, Philip (2012). Solar Photovoltaic Projects in the Mainstream Power Market. Oxford: Routledge. p. 240. ISBN 978-0-415-52048-5.
- "Solar Radiation on a Tilted Surface". PVEducation.org. Retrieved 22 April 2013.
- "Solar parks: maximising environmental benefits". Natural England. Retrieved 30 August 2012.
- "Person County Solar Park Makes Best Use of Solar Power and Sheep". solarenergy. Retrieved 22 April 2013.
- "Person County Solar Park One". Carolina Solar Energy. Retrieved 22 April 2013.
- "Solar Parks – Opportunities for Biodiversity". German Renewable Energies Agency. Retrieved 22 April 2013.
- "Addendum to conditional use permit". Kern County Planning and Community development Department. Retrieved 22 April 2013.
- "Smart Grid transmission scheme for Evacuation of Solar Power". Workshop on smart grid development. Pandit Deendayal Petroleum University. Retrieved 5 March 2013.
- "E.ON’s Solar PV Portfolio". E.On. Retrieved 22 April 2013.
- "Solar parks: maximising environmental benefits". Natural England. Retrieved 22 April 2013.
- "First solar park set for Upington, Northern Cape". Frontier Market Intelligence. Retrieved 22 April 2013.
- "ENFO entwickelt größtes Solarprojekt Deutschlands". Enfo AG. Retrieved 28 December 2012.
- "Solarpark Neuhardenberg - site plan". Wiki-Solar. Retrieved Jan 2013.
- "Qinghai leads in photovoltaic power". China Daily. 2 Mar 2012. Retrieved 21 February 2013.
- "Golmud Desert Solar Park - satellite view". Wiki-Solar. Retrieved 30 December 2012.
- "Free-field solar power plants a solution that allows power to be generated faster and more cost-effectively than offshore wind". OpenPR. Retrieved 5 March 2013.
- "Optimum Tilt of Solar Panels". MACS Lab. Retrieved 19 October 2014.
- "Tracked vs Fixed: PV system cost and AC power production comparison". WattSun. Retrieved 30 August 2012.
- "To Track or Not To Track, Part II". Report Snapshot. Greentech Solar. Retrieved 5 March 2013.
- "3-phase transformer". Conergy. Retrieved 5 March 2013.
- "Popua Solar Farm". Meridian Energy. Retrieved 22 April 2013.[dead link]
- "Solar cells and photovoltaic arrays". Photovoltaics. Alternative Energy News. Retrieved 5 March 2013.
- Kymakis, Emmanuel et al. "Performance analysis of a grid connected photovoltaic park on the island of Crete". Elsevier. Retrieved 30 December 2012.
- "Solar Report: Large photovoltaic power plants: average growth by almost 100 % since 2005". SolarServer. Retrieved 30 December 2012.
- "Mounting solar panels". 24 volt. Retrieved 5 March 2013.
- "Best Practice Guide for Photovoltaics (PV)". Sustainable Energy Authority of Ireland. Retrieved 30 December 2012.
- "PV Energy Conversion Efficiency". Solar Energy. Solarlux. Retrieved 5 March 2013.
- Mousazadeh, Hossain et al. "A review of principle and sun-tracking methods for maximizing". Renewable and Sustainable Energy Reviews 13 (2009) 1800–1818. Elsevier. Retrieved 30 December 2012.
- Appleyard, David. "Solar Trackers: Facing the Sun". Renewable Energy World. Retrieved 5 March 2013.
- Suri, Marcel et al. "Solar Electricity Production from Fixed-inclined and Sun-tracking c-Si Photovoltaic Modules in". Proceedings of 1st Southern African Solar Energy Conference (SASEC 2012), 21–23 May 2012, Stellenbosch, South Africa. GeoModel Solar, Bratislava, Slovakia. Retrieved 30 December 2012.
- Shingleton, J. "One-Axis Trackers – Improved Reliability, Durability, Performance, and Cost Reduction". National Renewable Energy Laboratory. Retrieved 30 December 2012.
- "Nellis Air Force Base Solar Power System". US Air Force. Retrieved 14 April 2013.
- "T20 Tracker". Data sheet. SunPower Corporation. Retrieved 14 April 2013.
- Li, Zhimin; et al. (June 2010). "Optical performance of inclined south-north single-axis tracked solar panels". Energy 10 (6): 2511–2516. doi:10.1016/j.energy.2010.02.050. Retrieved 5 March 2013.
- "Invert your thinking: Squeezing more power out of your solar panels". scientificamerican.com. Retrieved 9 June 2011.
- "Understanding Inverter Strategies". Solar Novus Today. Retrieved 13 April 2013.
- "Photovoltaic micro-inverters". SolarServer. Retrieved 13 April 2013.
- "Case study: German solar park chooses decentralized control". Solar Novus. Retrieved 13 April 2013.
- "Waldpolenz Solar Park". Juwi. Retrieved 13 April 2012.
- Lee, Leesa. "Inverter technology drives lower solar costs". Renewable Energy World. Retrieved 30 December 2012.
- "Solar Farm Fact Sheet". IEEE. Retrieved 13 April 2012.
- "Sandringham Solar Farm". Invenergy. Retrieved 13 April 2012.
- "McHenry Solar Farm". ESA. Retrieved 13 April 2013.
- "Woodville Solar Farm". Dillon Consulting Limited. Retrieved 13 April 2013.
- Appleyard, David. "Making waves: Inverters continue to push efficiency". Renewable Energy World. Retrieved 13 April 2013.
- "1 MW Brilliance Solar Inverter". General Electric Company. Retrieved 13 April 2013.
- "Planning aspects of solar parks". Ownergy Plc. Retrieved 13 April 2013.
- Larsson, Mats. "Coordinated Voltage Control". International Energy Agency. Retrieved 13 April 2013.
- "Long Island Solar Farm Goes Live!". Blue Oak Energy. Retrieved 22 April 2013. Retrieved 13 April 2013
- "Analysis of Transformer Failures". BPL Global. Retrieved 22 April 2013. Retrieved 13 April 2013
- Myers, D R (Sep 2003). "Solar Radiation Modeling and Measurements for Renewable Energy Applications: Data and Model Quality". Proceedings of International Expert Conference on Mathematical Modeling of Solar Radiation and Daylight. Retrieved 30 December 2012.
- Green, Martin; Emery, Keith; Hishikawa, Yoshihiro and Warta, Wilhelm; Hishikawa, Yoshihiro; Warta, Wilhelm (2009). "Solar Cell Efficiency Tables". Progress in Photovoltaics: Research and Applications 17: 85–94. doi:10.1002/pip.880. Retrieved 30 December 2012.
- Picault, D; et al.; Bacha, S.; de la Casa, J.; Aguilera, J. (2010). "Forecasting photovoltaic array power production subject to mismatch losses". Solar Energy 84 (7): 1301–1309. doi:10.1016/j.solener.2010.04.009. Retrieved 5 March 2013.
- Marion, B (et al). "Performance Parameters for Grid-Connected PV Systems". NREL. Retrieved 30 August 2012.
- "The Power of PV – Case Studies on Solar Parks in Eastern". Proceeding Renexpo. CSun. Retrieved 5 March 2013.
- "Avenal in ascendance: Taking a closer look at the world’s largest silicon thin-film PV power plant". PV-Tech. Retrieved 22 April 2013.
- "Outdoor PV Degradation Comparison". National Renewable Energy Laboratory. Retrieved 22 April 2013. Retrieved 13 April 2013
- "New Industry Leading Warrantee". REC Group. Retrieved 22 April 2013. Retrieved 13 April 2013
- "Westmill Solar Park". Westmill Solar Co-operative Ltd. Retrieved 30 December 2012.
- Grover, Sami. "World's Largest Community-Owned Solar Project Launches in England". Treehugger. Retrieved 30 December 2012.
- "Alternative Energy". Alternative Energy. Retrieved 7 March 2013.
- "independent power producer (IPP), non-utility generator (NUG)". Dictionary. Energy Vortex. Retrieved 30 December 2012.
- "Investor-owned utility". The Free Dictionary. Retrieved 30 December 2012.
- "Owners and IPPs". Deployment of utility-scale solar parks by company. Wiki-Solar. Retrieved 7 March 2013.
- Wang, Ucilia. "The Crowded Field of Solar Project Development". Renewable Energy World. Retrieved 30 December 2012.
- "Leadership across the Entire Value Chain". First Solar. Retrieved 7 March 2013.
- Englander, Daniel (18 May 2009). "Solar's New Important Players". Seeking Alpha. Retrieved 30 December 2012.
- "Solar farm on 20 acres of Kauai land gets county planning commission approval". Solar Hawaii. 15 July 2011. Retrieved 7 March 2013.
- "Aylesford – Certificate for grid connection". Aylesford Solar Park. AG Renewables. Retrieved 7 March 2013.
- "SunEdison Closes R2.6 Billion (US$314 Million) in Funding for 58 MW (AC) in South Africa Solar Projects". SunEdison. Retrieved 7 March 2013.
- "juwi starts build on its first solar park in South Africa". Renewable Energy Focus. 19 February 2013. Retrieved 7 March 2013.
- "Saudi Arabia’s Largest Solar Park Commissioned". Islamic Voice. 15 February 2013. Retrieved 7 March 2013.
- "Large scale solar parks". Know Your Planet. Retrieved 7 March 2013.
- "Statistics about some selected markets for utility-scale solar parks". Wiki-Solar. Retrieved 30 December 2012.
- HSE Assessment, Retrieved 08/15/2013
- "Τα "κομμάτια του πάζλ" μιας επένδυσης σε Φ/Β". Greek Photovoltaics Guide. Renelux. Retrieved 30 December 2012.
- "Connecting your new home, building or development to Ausgrid's electricity network". Ausgrid. Retrieved 30 December 2012.
- Final Installation Inspection, Retrieved 08/15/2013
- McHale, Maureen. "Not All O&M Agreements Are Alike". InterPV. Retrieved 30 December 2012.
- "Project Overview". Agua Caliente Solar Project. First Solar. Retrieved 7 March 2013.
- "Advantages Of Solar Energy". Conserve Energy Future. Retrieved 7 March 2013.
- "Addressing Solar Photovoltaic Operations and Maintenance Challenges". A Survey of Current Knowledge and Practices. Electric Power Research Institute (EPRI). Retrieved 30 December 2012.
- "IT for Renewable energy sources management". inAccess Networks. Retrieved 7 March 2013.
- "Solar Park Maintenance". BeBa Energy. Retrieved 7 March 2013.
- "Featured Array: Brewster Community Solar Garden® Facility". Retrieved 3 May 2013.
- "Featured Array: Strain Ranches". Retrieved 3 May 2013.
- "Talmage Solar Engineering, Inc. Unveils Largest Smart Array in North America". Retrieved 3 May 2013.
- "PV Power Plants 2012". p. 35. Retrieved 3 May 2013.
- For example, in the UK:. "Introduction to the Balancing and Settlement Code". Elexon. Retrieved 30 December 2012.
- Mitavachan, H. et al. "A case study of a 3-MW scale grid-connected solar photovoltaic power plant at Kolar, Karnataka". Renewable Energy Systems. Indian Institute of Science.
- "Electricity network delivery and access". UK Department of Energy and Climate Change. Retrieved 7 March 2013.
- "Renewable electricity". European Renewable Energy Council. Retrieved 31 July 2012.
- "Directive 2009/28/EC of the European Parliament and of the Council of 23 April 2009 on the promotion of the use of energy from renewable sources and amending and subsequently repealing Directives 2001/77/EC and 2003/30/EC". European Commission. Retrieved 7 March 2013.
- "2014 Outlook: Let the Second Gold Rush Begin". Deutsche Bank Markets Research. 2014-01-06. Archived from the original on 2014-11-22. Retrieved 2014-11-22.
- Giles Parkinson (2014-08-13). "Citigroup: Outlook for global solar is getting brighter". RenewEconomy. Retrieved 2014-08-18.
- "Solar power is beginning to go mainstream". Business Week. Retrieved 22 April 2013.
- http://www.iea.org (2014). "Technology Roadmap: Solar Photovoltaic Energy" (PDF). IEA. Archived from the original on 7 October 2014. Retrieved 7 October 2014.
- "Solar panels to keep getting cheaper". Evo Energy. 23 November 2012. Retrieved 7 March 2013.
|last1=in Authors list (help)
- Jago, Simon (6 March 2013). "Prices going one way". Energy Live News. Retrieved 7 March 2013.
- Burkart, Karl. "5 breakthroughs that will make solar power cheaper than coal". Mother Nature Network. Retrieved 7 March 2013.
- Spross, Jeff. "Solar Report Stunner: Unsubsidized ‘Grid Parity Has Been Reached In India’, Italy–With More Countries Coming in 2014". Climate Progress. Retrieved 22 April 2013.
- Morgan Baziliana et al. (17 May 2012). "Re-considering the economics of photovoltaic power". UN-Energy (United Nations). http://www.un-energy.org/stories/2498-re-considering-the-economics-of-photovoltaic-power. Retrieved 20 November 2012.
- "Solar Photovoltaics competing in the energy sector – On the road to competitiveness". EPIA. Retrieved 30 August 2012.
- Wolfe, Philip. "Priorities for low carbon transition". The politics of Climate Change. The Policy Network. Retrieved 7 March 2013.
- "Taxes and Incentives for renewable energy". KPMG. Retrieved 7 March 2013.
- "Policymaker's Guide to Feed-in Tariff Policy Design". National Renewable Energy Laboratory. Retrieved 22 April 2013. Couture, T., Cory, K., Kreycik, C., Williams, E., (2010). National Renewable Energy Laboratory, U.S. Dept. of Energy
- "What are Feed-in Tariffs". Feed-in Tariffs Limited. Retrieved 7 March 2013.
- "Race to the Top: The Expanding Role of U.S. State Renewable Portfolio Standards". University of Michigan. Retrieved 22 April 2013.
- "Investment in electricity generation - the role of costs, incentives and risks". UK Energy Research Centre. Retrieved 7 March 2013.
- "Solar Carve-Outs in Renewables Portfolio Standards". Dsire Solar. Retrieved 30 December 2012.
- "Innovative Technology Loan Guarantee Program". US DOE Loan Guarantee Program Office (LGPO). Retrieved 21 February 2012.
- "Independent Review: DOE’s Loan Guarantee Program Has Worked, Can Be Better". GreenTech Media. Retrieved 7 March 2013.
- "Production Tax Credit for Renewable Energy". Union of Concerned Scientists. Retrieved 30 August 2012.
- "Business Energy Investment Tax Credit (ITC).". US Department of Energy. Retrieved 21 February 2012.
- Directive 2009/28/EC of the European Parliament and of the Council "Renewables Directive". European Commission.
- Ragwitz, Mario, et al. "Assessment of National Renewable Energy Action Plans". REPAP 2020. Fraunhofer Institut. Retrieved 7 March 2013.
- Williams, Andrew (3 November 2011). "Project Helios: A brighter future for Greece?". Solar Novus Today. Retrieved 7 March 2013.
- "Clean Development Mechanism (CDM)". UNFCCC. Retrieved 30 December 2012.
- "CDM projects grouped in types". UNEP Risø Centre. Retrieved 7 March 2013.
- Ministry of New and Renewable Energy. "The Jawaharlal Nehru National Solar Mission". Scheme documents. Government of India. Retrieved 30 December 2012.
- Department for Resources, Energy and Tourism (11 Dec 2009). "Solar Flagships Program Open for Business". Government of Australia. Retrieved 30 December 2012.
- "South Africa: Renewable Energy Programme to Bring R47 Billion in Investment". allAfrica.com. 29 Oct 2012. Retrieved 30 December 2012.
- "Solar Energy". Ministry of Energy and Water Resources. Retrieved 30 December 2012.
- "Investment in Solar Parks". Solar Partner. Retrieved 7 March 2013.
- "Community ownership". FAQs. Westmill Solar Cooperative. Retrieved 7 March 2013.
- "What are time-of-use rates and how do they work?". Pacific Gas and Electric. Retrieved 7 March 2013.
- "Optimum Orientation of Solar Panels for Time-of-Use Rates". Macs Lab. Retrieved 22 April 2013.
- "The Optimum Financing Structure". Green Rhino Energy. Retrieved 7 March 2013.
- Belfiore, Francesco. "Optimizing PV Plant O&M Requires Focus on the Project Lifecycle". Renewable Energy World. Retrieved 7 March 2013.
- "Solar Photovoltaics competing in the energy sector – On the road to competitiveness". European Photovoltaic Industry Association. Retrieved 13 April 2013.
- "Global Market Outlook for Photovoltaics 2014-2018". http://www.epia.org. EPIA - European Photovoltaic Industry Association. Archived from the original on 12 June 2014. Retrieved 12 June 2014.
- "Renewable Power, Policy, and the Cost of Capital". UNEP/BASE Sustainable Energy Finance Initiative. Retrieved 22 April 2013. Retrieved 13 April 2013
- "Global utility-scale solar capacity climbs through 21GW in 2013". Renew Economy. 23 January 2014. Retrieved 27 February 2014.
- "Deployment of utility-scale solar parks - by country". Wiki-Solar.org. Retrieved 27 February 2014.
- Hill, Joshua (22 February 2013). "Giant Solar Farm Capacity Doubling Inside 12 Months Breaking 12 GW". Clean Technica. Retrieved 7 March 2013.
- "Project search". CDM: Project activities. UNFCCC. Retrieved 7 March 2013.
- "Northwest China Grid Company Limited". Northwest China Grid Company Limited. Retrieved 22 April 2013.
- "In Hemau liefert der weltweit größte Solarpark umweltfreundlichen Strom aus der Sonne" (in German). Stadt Hemau. Retrieved 13 April 2013.
- "Best of Both Worlds: What if German installation costs were combined with the best solar resources?". National Renewable Energy Laboratory. Retrieved 22 April 2013. Retrieved 13 April 2013
- "Leipziger Land project". Geosol. Retrieved 13 April 2013.
- Olson, Syanne (14 January 2011). "IBC Solar completes grid connection for 13.8MW German solar park". PV-Tech. Retrieved 7 March 2013.
- "Eastern Germany's sunny future". CNN. Retrieved 22 April 2013.[dead link] Retrieved 13 April 2013
- "German PV Funding Up In The Air Again". SolarBuzz. Retrieved 22 April 2013. Retrieved 13 April 2013
- "Goodnight Sunshine". Slate. Retrieved 22 April 2013. Retrieved 13 April 2013
- "Gujarat Solar Park Inauguration at Charanka, Gujarat". Indian Solar Summit. 19 April 2012. Retrieved 7 March 2013.
- "Sun cities? Rajasthan solar projects under a cloud". Times of India. Retrieved 22 April 2013. Retrieved 13 April 2013
- "Top 10 Solar PV Power Plants". InterPV. Retrieved 22 April 2013. Retrieved 13 April 2013
- Rosenthal, Elisabeth (8 March 2010). "Solar Industry Learns Lessons in Spanish Sun". New York Times. Retrieved 7 March 2013.
- "Solar parks in the UK". WolfeWare. Retrieved 13 April 2013.
- Hughes, Emma (3 August 2011). "Updated: Just how many solar projects beat the fast-track review?". Solar Power Portal. Retrieved 3 July 2013.
- Feed-in tariff cut shocks UK PV market "Feed-in tariff cut shocks UK PV market". greenbang.com. 28 March 2011. Retrieved 29 March 2011.
- "UK tops Europe’s utility-scale solar market for 2013". Wiki-Solar. 6 June 2013. Retrieved 3 July 2013.
- "UK becomes Europe's top utility-scale solar market". Photon International. 7 June 2013. Retrieved 3 July 2013.
- "Solar parks map - United Kingdom". Wiki-Solar. Retrieved 13 April 2013.
- "Wales' first solar park powers up in Pembrokeshire". BBC. 8 July 2011. Retrieved 25 June 2014.
- "Solar parks: Large scale schemes 'to double' in Wales". BBC. 25 June 2014. Retrieved 25 June 2014.
- "California Renewables Portfolio Standard (RPS)". California Public Utilities Commission. Retrieved 7 March 2013.
- "Nevada Energy Portfolio Standard". Database of State Incentives for Renewables & Efficiency. US Department of Energy. Retrieved 7 March 2013.
- "Arizona Energy Portfolio Standard". Database of State Incentives for Renewables & Efficiency. US Department of Energy. Retrieved 7 March 2013.
- The locations of these and other plants over 10MW are illustrated in. "Solar Parks mapping". Wiki-Solar. Retrieved 13 April 2013.
- Note that nominal power may be AC or DC, depending on the plant. See "AC-DC conundrum: Latest PV power-plant ratings follies put focus on reporting inconsistency (update)". PV-Tech. Retrieved 22 April 2013. Retrieved 13 April 2013
- "The world’s largest photovoltaic solar power plant is in Pocking". Solar Server. Retrieved 30 August 2012.
- "Nellis Airforce Base solar power system". United States Air Force. Retrieved 30 August 2012.
- "The Olmedilla Solar Park". Retrieved 30 August 2012.
- "24 MW: SinAn, South Korea". Conergy. Retrieved 30 August 2012.
- "DeSoto Next Generation Solar Energy Center". Florida Power and Light. Retrieved 30 August 2012.
- "EDF Energies Nouvelles secures building permits for two solar power plants (15.3 MW) on Reunion Island". EDF Energies Nouvelles. 23 Jul 2008. Retrieved 30 August 2012.
- "Sarnia Solar Project celebration". Enbridge. Retrieved 30 August 2012.
- "Chint Solar successfully completed Golmud 20MW photovoltaic power station". PVsolarChina.com. Retrieved 30 August 2012.
- "FinowTower I + II; Mit 84,7 MWp das größte Solarstrom-Kraftwerk Europas". SolarHybrid. Retrieved 30 August 2012.
- "Lopburi Solar Farm". CLP Group. Retrieved 30 August 2012.
- "Activ Solar Commissions 100-Plus MW Perovo Solar PV Station in Ukraine’s Crimea". Clean Technica. 29 Dec 2011. Retrieved 30 August 12. Check date values in:
- "Gujarat's Charanka Solar Park". Energy Insight. 25 Apr 2012. Retrieved 30 August 2012.
- "Gujarat's Charanka Solar Park". Retrieved 3 May 2013.
- "Agua Caliente Solar Project". First Solar. Retrieved 31 August 2012.
- Leader, Jessica (10 October 2012). "Australia's Greenough River Solar Farm Opens Amid Renewable Target Debate". Huffington Post. Retrieved 22 April 2013., Reuters, Rebekah Kebede, 9 October 2012 Retrieved 13 April 2013
- "President Humala inaugurates T-Solar Group photovoltaic solar-power plants in Peru". Retrieved 19 April 2013.
- "Biggest Community-Owned Solar Array In US Now Online". Clean Technica. 27 December 2012. Retrieved 28 February 2013.
|last1=in Authors list (help)
- "Sheikh Zayed site location". Retrieved 19 April 2013.
- "Shaikh Zayed Solar Power Plant in Mauritania inaugurated by Shaikh Saeed". Gulf News. 18 April 2013. Retrieved 19 April 2013.
|last1=in Authors list (help)
- "USA overtakes Germany in race against China for 3GW of utility scale solar as Topaz project starts to connect". Wiki-Solar. 3 June 2013. Retrieved 3 July 2013.
|Wikimedia Commons has media related to Photovoltaic power stations.|
- Interactive mapping of worldwide projects over 10MW
- Solar Energy Industry Association - Large Solar Projects in the US
- The top 10 PV Solar power stations in the world (2014)
- List of 1000 largest photovoltaic power plants (as of 2011)