Floating solar

Floating solar or floating photovoltaics (FPV), sometimes called floatovoltaics, is solar panels mounted on a structure that floats on a body of water, typically a reservoir or a lake.

Floating photovoltaic

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.[1] Installed power reached 3 GW in 2020, with 10 GW predicted by 2025.[2]

The costs for a floating system are 20-25% higher than for ground-mounted systems.[3]

Technology featuresEdit

There are several reasons for this development:

  1. 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.[4]
  2. Installation and decommissioning: 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.
  3. Water conservation and water quality: Partial coverage of water basins can reduce water evaporation. 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.[5] This may be greater in Australia, and is a very useful feature if the basin is used for irrigation purposes.[6][7]
  4. Cooling: cooling the floating structure is simple. 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).[8] In these cases the global PV modules efficiency rises thanks to the absence of thermal drift,[clarification needed] with a gain in energy harvesting up to 8-10%.
  5. 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%.[9]
  6. Storage opportunity: The presence of water naturally suggests using gravitational energy storage, mainly in the coupling with hydroelectric basins. However, other (inefficient) possibilities have been explored and in particular compressed-air energy storage systems have been suggested.[10]
  7. Environment control: Algal blooms, a serious problem in industrialized countries, may be reduced. The partial coverage of the basins and the reduction of light on biological fouling just below the surface, together with active systems, can solve this problem. Partial coverage is only a part of the more general problem of managing a water basin generated by and/or polluted by industrial activities.[11]
  8. Efficiency improvement: Many studies claim that solar panels over water are more efficient. The energy gain reported range from 5% to 15%.[12][13][14]

Floating solar is often installed on existing hydropower.[15]

ChallengesEdit

Floating solar presents several challenges to designers:[16][17]

  1. 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.
  2. 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.
  3. Maintenance complexity: Operation and maintenance activities are, as a general rule, more difficult to perform on water than on land.

HistoryEdit

 
Installed capacity worldwide in MW[18]

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.[19]

The MIRARCO (Mining Innovation Rehabilitation and Applied Research Corporation Ontario, CANADA) research group quotes several solutions that were put forward in 2008-2011 and 2012-2014.[1] Most of the installations can be classified into three categories:

  • PV plants constituted by modules mounted on pontoons
  • PV modules mounted on rafts built in plastic and galvanized steel
  • PV modules mounted on rafts, fully in plastic.

A 45 MW combined solar and hydropower plant was installed in Thailand in 2021.[20] A 320 MW facility opened in China in 2022.[21]

Largest floating solar facilitiesEdit

Floating photovoltaic power stations (5 MW and larger)
PV power station Location Country Nominal Power[22]

(MWp)

Notes
Dezhou Dingzhuang China 320 +100 MW windpower[21][23]
Three Gorges Huainan City, Anhui China 150 [23]
Tata Power Solar Kayamkulam, Kerala India 100
Ramagundam Peddapalli, Telangana India 100
CECEP China 70 [23]
Tengeh Singapore 60 [23][24][25]
Sirindhorn Dam Thailand 9 +36 MW hydropower[26]
Sayreville, New Jersey USA 4.4 [27]

ReferencesEdit

  1. ^ a b Trapani, 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.
  2. ^ 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.
  3. ^ Martín, José Rojo (2019-10-27). "BayWa r.e. adds to European floating solar momentum with double project completion". PV Tech. Archived from the original on 2019-11-11. Retrieved 2019-11-11.
  4. ^ 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)
  5. ^ "Do floating solar panels work better?".{{cite web}}: CS1 maint: url-status (link)
  6. ^ 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. ISSN 0960-1481.
  7. ^ Hassan, M.M. and Peyrson W.L. (2016). "Evaporation mitigation by floating modular devices". Earth and Environmental Science. 35.
  8. ^ 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.
  9. ^ 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)
  10. ^ R. Cazzaniga, M. Cicu, M. Rosa-Clot, P. Rosa-Clot, G. M. Tina and C. Ventura (2017). "Compressed air energy storage integrated with floating photovoltaic plant". Journal of Energy Storage. 13: 48–57. doi:10.1016/j.est.2017.06.006. S2CID 115709382.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  11. ^ 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: 898–905.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  12. ^ 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.
  13. ^ "Floating Solar On Pumped Hydro, Part 1: Evaporation Management Is A Bonus". CleanTechnica. 27 December 2019.
  14. ^ "Floating Solar On Pumped Hydro, Part 2: Better Efficiency, But More Challenging Engineering". CleanTechnica. 27 December 2019.
  15. ^ World Bank Group, ESMAP, and SERIS. 2018. Where Sun Meets Water: Floating Solar Market Report - Executive Summary. Washington, DC: World Bank.
  16. ^ Floating Solar (PV) Systems: why they are taking off. By Dricus De Rooij, Aug 5 2015
  17. ^ Where Sun Meets Water, FLOATING SOLAR MARKET REPORT. World Bank, 2019.
  18. ^ Data taken from "Where Sun Meets Water: Floating Solar Market Report," World Bank Group and SERIS, Singapore, 2018.
  19. ^ M. Rosa-Clot and P. Rosa-Clot (2008). "Support and method for increasing the efficiency of solar cells by immersion". Italy Patent PI2008A000088.
  20. ^ "Thailand switches on 45MW floating solar plant, plans for 15 more". RenewEconomy. 11 November 2021.
  21. ^ a b 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.
  22. ^ 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
  23. ^ a b c d "5 Largest Floating Solar Farms in the World in 2022". YSG Solar. 20 January 2022.
  24. ^ Martín, José Rojo (2019-06-06). "Singaporean water utility in push for 50MW-plus floating PV". PV Tech.
  25. ^ "Singapore launches large-scale floating solar farm in Tengeh Reservoir". www.datacenterdynamics.com. 27 July 2021. Archived from the original on 6 August 2021.
  26. ^ "Thailand's massive floating solar farm lays the foundation for its emission-free future". ZME Science. 10 March 2022.
  27. ^ "New Jersey outfit kicks off construction of 9MW floating solar array". Offshore Energy. 4 May 2022.

BibliographyEdit