Systems of solar cell panels installed on a structure that floats on a body of water
Floating photovoltaic on an irrigation pond
Floating solar or floating photovoltaics (FPV), sometimes called floatovoltaics, are solar panels mounted on a structure that floats on a body of water, typically a reservoir or a lake such as drinking water reservoirs, quarry lakes, irrigation canals or remediation and tailing ponds.[1][2][3][4][5]
The systems can have advantages over photovoltaics (PV) on land. Water surfaces may be less expensive than the cost of land, and there are fewer rules and regulations for structures built on bodies of water not used for recreation. Life cycle analysis indicates that foam-based FPV[6] have some of the shortest energy payback times (1.3 years) and the lowest greenhouse gas emissions to energy ratio (11 kg CO2 eq/MWh) in crystalline silicon solar photovoltaic technologies reported.[7]
Floating arrays can achieve higher efficiencies than PV panels on land because water cools the panels. The panels can have a special coating to prevent rust or corrosion.[8]
The market for this renewable energy technology has grown rapidly since 2016. The first 20 plants with capacities of a few dozen kWp were built between 2007 and 2013.[9] Installed power grew from 3 GW in 2020, to 13 GW in 2022,[10] surpassing a prediction of 10 GW by 2025.[11] The World Bank estimated there are 6,600 large bodies of water suitable for floating solar, with a technical capacity of over 4,000 GW if 10% of their surfaces were covered with solar panels.[10]
The costs for a floating system are about 10-20% higher than for ground-mounted systems.[12][13][14] According to a researcher at the National Renewable Energy Laboratory (NREL), this increase is primarily due to the need for anchoring systems to secure the panels on water, which contributes to making floating solar installations about 25% more expensive than those on land.[15]
History
Energy production from floating solar photovoltaic sources expanded dramatically in the last half of the 2010s, and is forecast to grow exponentially in the early 2020s.[16]
American, Danish, French, Italian and Japanese nationals were the first to register patents for floating solar. In Italy the first registered patent regarding PV modules on water goes back to February 2008.[17]
In May 2008, the Far Niente Winery in Oakville, California, installed 994 solar PV modules with a total capacity of 175 kW onto 130 pontoons and floating them on the winery's irrigation pond.[9][19] Several small-scale floating PV farms were built over the next seven years. The first megawatt-scale plant was commissioned in July 2013 at Okegawa, Japan.
In 2016, Kyocera developed what was then the world's largest, a 13.4 MW farm on the reservoir above Yamakura Dam in Chiba Prefecture[20] using 50,000 solar panels.[21][22] The Huainan plant, inaugurated in May 2017 in China, occupies more than 800000 m2 on a former quarry lake, capable of producing up to 40 MW.[23]
Salt-water resistant floating farms are also being constructed for ocean use.[24]
Floating solar panels are rising in popularity, in particular in countries where the land occupation and environmental impact legislations are hindering the rise of renewable power generation capabilities.
Global installed capacity passed 1 GW in 2018 and reached 13 GW in 2022, mostly in Asia.[10] One project developer, Baywa r.e., reported another 28 GW of planned projects.[10]
Installation
The construction process for a floating solar project includes installing anchors and mooring lines that attach to the waterbed or shore, assembling floats and panels into rows and sections onshore, and then pulling the sections by boat to the mooring lines and secured into place.[14]
Advantages
There are several reasons for this development:
No land occupancy: The main advantage of floating PV plants is that they do not take up any land, except the limited surfaces necessary for electric cabinet and grid connections. Their price is comparable with land based plants, but floatovoltaics provide a good way to avoid land consumption.[25]
Installation, decommissioning and maintenance: Floating PV plants are more compact than land-based plants, their management is simpler and their construction and decommissioning straightforward. The main point is that no fixed structures exist like the foundations used for a land-based plant so their installation can be totally reversible. Furthermore panels installed on water basins require less maintenance in particular when compared with installation on ground with dusty soil. As arrays are assembled at a single shore point before being moved into place, installations can be faster than ground-mounted arrays.[10]
Water conservation and water quality: Partial coverage of water basins can reduce water evaporation.[26] This result depends on climate conditions and on the percentage of the covered surface. In arid climates such as parts of India this is an important advantage since about 30% of the evaporation of the covered surface is saved.[27] This may be greater in Australia, and is a very useful feature if the basin is used for irrigation purposes.[28][29] Water conservation from FPV is substantial and can be used to protect disappearing terminal natural lakes[30] and other bodies of fresh water.[31]
Increased panel efficiency due to cooling: the cooling effect of the water close to the PV panels leads to an energy gain that ranges from 5% to 15%.[6][32][33][34] Natural cooling can be increased by a water layer on the PV modules or by submerging them, the so-called SP2 (Submerged Photovoltaic Solar Panel).[35]
Tracking: Large floating platforms can easily be rotated horizontally and vertically to enable Sun-tracking (similar to sunflowers). Moving solar arrays uses little energy and doesn't need a complex mechanical apparatus like land-based PV plants. Equipping a floating PV plant with a tracking system costs little extra while the energy gain can range from 15% to 25%.[36]
Environment control: Algal blooms, a serious problem in industrialized countries, may be reduced when greater than 40% of the surface is covered.[37] Coverage of water basins reduces light just below the surface, reducing algal photosynthesis and growth. Active pollution control remains important for water management.[38]
Utilization of areas already exploited by human activity: Floating solar plants can be installed over water basins artificially created such as flooded mine pits[39] or hydroelectric power plants. In this way it is possible to exploit areas already influenced by the human activity to increase the impact and yield of a given area instead of using other land.
Hybridization with hydroelectric power plants: A: Sun. B: Floating solar panels. C: Inverter. D: Electric connection cabinet. E: electricity grid. F: water intake. G: pumped water canal. H: pump/turbine body. I: discharge. Floating solar is often installed on existing hydropower.[40] This allows for additional benefits and cost reductions such as using the existing transmission lines and distribution infrastructure.[41] FPV provides a potentially profitable means of reducing water evaporation in the world's at-risk bodies of fresh water. Furthermore it is possible to install floating photovoltaic panels on the water basins of pumped-storage hydroelectric power plant. The hybridization of solar photovoltaic with pumped storage is beneficial in rising the capability of the two plant combined because the pumped hydroelectric plant can be used to store the high but unstable amount of electricity coming from the solar PV, making the water basin acting as a battery for the solar photovoltaic plant.[42] For example, a case study of Lake Mead found that if 10% of the lake was covered with FPV, there would be enough water conserved and electricity generated to service Las Vegas and Reno combined.[31] At 50% coverage, FPV would provide over 127 TWh of clean solar electricity and 633.22 million m3 of water savings, which would provide enough electricity to retire 11% of the polluting coal-fired plants in the U.S. and provide water for over five million Americans, annually.[31]
Disadvantages
Floating solar presents several challenges to designers:[43][44][45][46]
Electrical safety and long-term reliability of system components: Operating on water over its entire service life, the system is required to have significantly increased corrosion resistance and long-term floatation capabilities (redundant, resilient, distributed floats), particularly when installed over salt water.
Waves: The floating PV system (wires, physical connections, floats, panels) needs to be able to withstand relatively higher winds (than on land) and heavy waves, particularly in off-shore or near-shore installations.
Maintenance complexity: Operation and maintenance activities are, as a general rule, more difficult to perform on water than on land.
Floating technology complexity: Floating PV panels have to be installed over floating platforms such as pontoons or floating pears. This technology was not initially developed for accommodating solar modules thus needs to be designed specifically for that purpose.
Anchoring technology complexity: Anchoring the floating panels is fundamental in order to avoid abrupt variation of panels position that would hinder the production. Anchoring technology is well known and established when applied to boats or other floating objects but it needs to be adapted to the usage with floating PV. Recent severe storms have caused floating systems to fail and anchoring systems must be developed with these risks in mind.[47]
Largest floating solar facilities
This list is incomplete; you can help by adding missing items. (May 2022)
Floating photovoltaic power stations (5 MW and larger)[48]
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^"Running Out of Precious Land? Floating Solar PV Systems May Be a Solution". EnergyWorld.com. 7 November 2013. Archived from the original on 26 December 2014. Retrieved 11 June 2016.
^"Vikram Solar commissions India's first floating PV plant". SolarServer.com. 13 January 2015. Archived from the original on 2 March 2015.
^"Sunflower Floating Solar Power Plant In Korea". CleanTechnica. 21 December 2014. Archived from the original on 15 May 2016. Retrieved 11 June 2016.
^"Short Of Land, Singapore Opts For Floating Solar Power Systems". CleanTechnica. 5 May 2014. Archived from the original on 14 March 2016. Retrieved 11 June 2016.
^ abMayville, Pierce; Patil, Neha Vijay; Pearce, Joshua M. (2020-12-01). "Distributed manufacturing of after market flexible floating photovoltaic modules". Sustainable Energy Technologies and Assessments. 42: 100830. doi:10.1016/j.seta.2020.100830. ISSN 2213-1388. S2CID 225132653.
^Hayibo, Koami Soulemane; Mayville, Pierce; Pearce, Joshua M. (2022-03-01). "The greenest solar power? Life cycle assessment of foam-based flexible floatovoltaics". Sustainable Energy & Fuels. 6 (5): 1398–1413. doi:10.1039/D1SE01823J. ISSN 2398-4902. S2CID 246498822.
^Goode, Erica (2016-05-20). "New Solar Plants Generate Floating Green Power". The New York Times. ISSN 0362-4331. Retrieved 2023-01-25.
^ abcTrapani, Kim; Redón Santafé, Miguel (2015). "A review of floating photovoltaic installations: 2007-2013". Progress in Photovoltaics: Research and Applications. 23 (4): 524–532. doi:10.1002/pip.2466. hdl:10251/80704. S2CID 98460653.
^ abcde"Floating Solar Panels Turn Old Industrial Sites Into Green Energy Goldmines". Bloomberg.com. 2023-08-03. Retrieved 2023-08-03.
^Hopson (58da34776a4bb), Christopher (2020-10-15). "Floating solar going global with 10GW more by 2025: Fitch | Recharge". Recharge | Latest renewable energy news. Retrieved 2021-10-18.{{cite web}}: CS1 maint: numeric names: authors list (link)
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^ abc"Long popular in Asia, floating solar catches on in US". AP NEWS. 2023-05-10. Retrieved 2023-05-11.
^ abLudt, Billy (2023-01-20). "Buoyant racking turns water into an ideal solar site". Solar Power World. Retrieved 2024-07-15.
^"How Floating Solar Panels Are Being Used to Power Electric Grids". Bloomberg.com. 2023-03-07. Retrieved 2024-04-21.
^Cazzaniga, Raniero; Rosa-Clot, Marco (1 May 2021). "The booming of floating PV". Solar Energy. 219: 3–10. Bibcode:2021SoEn..219....3C. doi:10.1016/j.solener.2020.09.057. S2CID 225126249.
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^"Winery goes solar with Floatovoltaics". SFGate. 29 May 2008. Archived from the original on 7 May 2013. Retrieved 31 May 2013.
^"Yamakura Dam in Chiba Prefecture". The Japan Dam Foundation. Archived from the original on 2 February 2015. Retrieved 1 February 2015.
^Kyocera and Century Tokyo Leasing to Develop 13.4MW Floating Solar Power Plant on Reservoir in Chiba Prefecture, Japan Archived 25 June 2016 at the Wayback Machine, Kyocera, 22 December 2014
^New Solar Plants Generate Floating Green Power Archived 28 December 2016 at the Wayback Machine NYT 20 May 2016
^"The world's largest floating solar power plant has come into operation in China". mashable.france24.com. May 26, 2017. Retrieved June 10, 2017.
^Solar Panels Floating on Water Could Power Japan's Homes Archived 11 June 2016 at the Wayback Machine, National Geographic, Bryan Lufkin, 16 January 2015
^R. Cazzaniga, M. Rosa-Clot, P. Rosa-Clot and G. M. Tina (2018). "Geographic and Technical Floating Photovoltaic Potential". Thermal Energy Science.{{cite journal}}: CS1 maint: multiple names: authors list (link)
^"Floating PV; an assessment of water quality and evaporation reduction in semi-arid regions".
^Choi, Y.-K. and N.-H. Lee (2013). "Empirical Research on the efficiency of Floating PV systems compared with Overland PV Systems". Conference Proceedings of CES-CUBE.
^"Floating Solar On Pumped Hydro, Part 1: Evaporation Management Is A Bonus". CleanTechnica. 27 December 2019.
^"Floating Solar On Pumped Hydro, Part 2: Better Efficiency, But More Challenging Engineering". CleanTechnica. 27 December 2019.
^Choi, Y.K. (2014). "A study on power generation analysis on floating PV system considering environmental impact". Int. J. Softw. Eng. Appl. 8: 75–84.
^R. Cazzaniga, M. Cicu, M. Rosa-Clot, P. Rosa-Clot, G. M. Tina and C. Ventura (2018). "Floating photovoltaic plants: performance analysis and design solutions". Renewable and Sustainable Reviews. 81: 1730–1741. doi:10.1016/j.rser.2017.05.269.{{cite journal}}: CS1 maint: multiple names: authors list (link)
^Pouran, Hamid M.; Padilha Campos Lopes, Mariana; Nogueira, Tainan; Alves Castelo Branco, David; Sheng, Yong (2022-11-18). "Environmental and technical impacts of floating photovoltaic plants as an emerging clean energy technology". iScience. 25 (11): 105253. Bibcode:2022iSci...25j5253P. doi:10.1016/j.isci.2022.105253. ISSN 2589-0042. PMC 9587316. PMID 36281449.
^Trapani, K. and Millar, B. (2016). "Floating photovoltaic arrays to power mining industry: a case study for the McFaulds lake (ring of fire)". Sustainable Energy. 35 (3): 898–905. Bibcode:2016EPSE...35..898T. doi:10.1002/ep.12275.{{cite journal}}: CS1 maint: multiple names: authors list (link)
^Song, Jinyoung; Choi, Yosoon (2016-02-10). "Analysis of the Potential for Use of Floating Photovoltaic Systems on Mine Pit Lakes: Case Study at the Ssangyong Open-Pit Limestone Mine in Korea". Energies. 9 (2): 102. doi:10.3390/en9020102.
^World Bank Group, ESMAP, and SERIS. 2018. Where Sun Meets Water: Floating Solar Market Report - Executive Summary. Washington, DC: World Bank.
^Rauf, Huzaifa; Gull, Muhammad Shuzub; Arshad, Naveed (2019-02-01). "Integrating Floating Solar PV with Hydroelectric Power Plant: Analysis of Ghazi Barotha Reservoir in Pakistan". Energy Procedia. Innovative Solutions for Energy Transitions. 158: 816–821. Bibcode:2019EnPro.158..816R. doi:10.1016/j.egypro.2019.01.214. ISSN 1876-6102. S2CID 115606663.
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^Floating Solar (PV) Systems: why they are taking off. By Dricus De Rooij, Aug 5 2015
^Where Sun Meets Water, FLOATING SOLAR MARKET REPORT. World Bank, 2019.
^[1] Floating solar is more than panels on a platform—it’s hydroelectric’s symbiont | Ars Technica
^"Storm damages world's biggest floating solar plant in Madhya Pradesh". The Times of India. 15 April 2024.
^"Top 50 Operational Floating Solar Projects". SolarPlaza. Retrieved 2023-06-07.
^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) Archived 2011-01-19 at the Wayback Machine
^Garanovic, Amir (2021-12-20). "China connects 550MW combined floating solar and aquaculture project to power grid". Offshore Energy. Retrieved 2023-08-16.
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^"Hexa, Ciel & Terre complete Taiwan extension". 20 February 2024.
^Lee, Andrew (5 January 2022). "'Smooth operator': world's largest floating solar plant links with wind and storage". Recharge | Latest renewable energy news. Archived from the original on 11 March 2022.
^ abcd"5 Largest Floating Solar Farms in the World in 2022". YSG Solar. 20 January 2022.
^"Jokowi inaugurates Southeast Asia's largest floating solar farm". The Jakarta Post. Retrieved 2023-11-09.
^ abcde"Floating PV System - Commercial solar photovoltaic installers". en.sungrowpower.com. Retrieved 2023-03-14.
^"Anhui CECEP, CHINA". Ciel et Terre. Retrieved 2023-02-16.
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^"Singapore launches large-scale floating solar farm in Tengeh Reservoir". www.datacenterdynamics.com. 27 July 2021. Archived from the original on 6 August 2021.
^Garanovic, Amir (2023-05-08). "Multi-megawatt floating solar farm comes online in Thailand". Offshore Energy. Retrieved 2023-05-11.
^"Da Mi Floating Solar Power Plant successfully connected to grid". en.evn.com.vn. Retrieved 2023-06-07.
^"Thailand switches on 45MW floating solar plant, plans for 15 more". RenewEconomy. 11 November 2021.
^"Thailand's massive floating solar farm lays the foundation for its emission-free future". ZME Science. 10 March 2022.
^"Giant Floating Solar Flowers Offer Hope for Coal-Addicted Korea". Bloomberg.com. 2022-02-28. Retrieved 2023-03-14.
^"Anhui GCL, CHINA". Ciel et Terre. Retrieved 2023-02-16.
^Largue, Pamela (2023-09-13). "Israel's Teralight inaugurates 31MW floating solar project". Power Engineering International. Retrieved 2023-09-18.
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Further reading
Almeida, Rafael M.; Schmitt, Rafael; Grodsky, Steven M.; Flecker, Alexander S.; Gomes, Carla P.; Zhao, Lu; Liu, Haohui; Barros, Nathan; Kelman, Rafael; McIntyre, Peter B. (2022-06-07). "Floating solar power could help fight climate change — let's get it right". Nature. 606 (7913): 246–249. Bibcode:2022Natur.606..246A. doi:10.1038/d41586-022-01525-1. PMID 35672509. S2CID 249465577.
Howard, E. and Schmidt, E. 2008. Evaporation control using Rio Tinto's Floating Modules on Northparks Mine, Landloch and NCEA. National Centre for Engineering in Agriculture Publication 1001858/1, USQ, Toowoomba.
R. Cazzaniga, M. Cicu, M. Rosa-Clot, P. Rosa-Clot, G. M. Tina and C. Ventura (2017). "Floating Photovoltaic plants: performance analysis and design solutions". Renewable and Sustainable Energy Reviews. 81: 1730–1741. doi:10.1016/j.rser.2017.05.269.{{cite journal}}: CS1 maint: multiple names: authors list (link)
Taboada, M.E.; Cáceres, L.; Graber, T.A.; Galleguillos, H.R.; Cabeza, L.F.; Rojas, R. (2017). "Solar water heating system and photovoltaic floating cover to reduce evaporation: Experimental results and modeling". Renewable Energy. 105: 601–615. doi:10.1016/j.renene.2016.12.094. hdl:10459.1/59048.
Chang, Yuan-Hsiou; Ku, Chen-Ruei; Yeh, Naichia (2014). "Solar powered artificial floating island for landscape ecology and water quality improvement". Ecological Engineering. 69: 8–16. Bibcode:2014EcEng..69....8C. doi:10.1016/j.ecoleng.2014.03.015.
Ho, C.J.; Chou, Wei-Len; Lai, Chi-Ming (2016). "Thermal and electrical performances of a water-surface floating PV integrated with double water-saturated MEPCM layers". Applied Thermal Engineering. 94: 122–132. Bibcode:2016AppTE..94..122H. doi:10.1016/j.applthermaleng.2015.10.097.
M. Rosa-Clot, G. M. Tina (2017). Submerged and Floating Photovoltaic Systems Modelling, Design and Case Studies. Academic Press.
Sahu, Alok; Yadav, Neha; Sudhakar, K. (2016). "Floating photovoltaic power plant: A review". Renewable and Sustainable Energy Reviews. 66: 815–824. doi:10.1016/j.rser.2016.08.051.
Trapani, Kim; Millar, Dean L. (2013). "Proposing offshore photovoltaic (PV) technology to the energy mix of the Maltese islands". Energy Conversion and Management. 67: 18–26. Bibcode:2013ECM....67...18T. doi:10.1016/j.enconman.2012.10.022.
Siecker, J.; Kusakana, K.; Numbi, B.P. (2017). "A review of solar photovoltaic systems cooling technologies". Renewable and Sustainable Energy Reviews. 79: 192–203. doi:10.1016/j.rser.2017.05.053.
Spencer, Robert S.; Macknick, Jordan; Aznar, Alexandra; Warren, Adam; Reese, Matthew O. (2019-02-05). "Floating Photovoltaic Systems: Assessing the Technical Potential of Photovoltaic Systems on Man-Made Water Bodies in the Continental United States". Environmental Science & Technology. 53 (3): 1680–1689. Bibcode:2019EnST...53.1680S. doi:10.1021/acs.est.8b04735. ISSN 0013-936X. OSTI 1489330. PMID 30532953. S2CID 54471924.
Ludt, Billy (2023-01-20). "Buoyant racking turns water into an ideal solar site". Solar Power World. Retrieved 2023-02-13.