International Applications for Floating Solar

To ensure reliable, affordable, and sustainable future power supplies, many developing countries are exploring options for new electricity generation. Floating solar photovoltaics (FPV) are becoming an increasingly competitive option; however, the technology is still nascent, and many potential adopters have questions about the underlying technology, its benefits, and how to analyze it appropriately. The U.S. Department of Energy’s National Laboratory (NREL) is a leader in FPV and is looking to develop international implementation, analysis, and research collaborations to further advance the technology and support global deployment. This concept note provides an overview of FPV and potential areas of collaboration.1

What are Floating Solar To date, FPV has predominantly been onshore, and electricity is transmitted Photovoltaics, and Why installed on artificial water bodies from the FPV system to this equipment (e.g., treated wastewater storage ponds, and the grid or load via underwater are They Interesting? reservoirs, and agricultural irrigation cables (Trapani and Redón Santafé FPV systems represent an emerging or retention ponds). The PV module 2015; Sahu, Yadav, and Sudhakar opportunity in which solar photovoltaic technology deployed with FPV is similar 2016; Krishnaveni, Anbarasu, and (PV) systems are sited directly on to traditional ground-or-roof-mounted Vigneshkumar 2016). water bodies, such as lakes, ponds, or systems, but the modules are mounted reservoirs. Technological advances on a floating platform made of plastic Where, When, and How are and the falling capital costs of PV and stainless steel (Sahu, Yadav, and Floating Solar Photovoltaics modules have dramatically increased Sudhakar 2016; Pickerel 2016; Choi Being Deployed? the cost competitiveness of 2014; Choi, Lee, and Kim 2013; Redón over the last several years (IRENA Santafé et al. 2014). Typically, multiple FPV systems are commercially 2018). Specific interest in FPV has floating platforms are connected with available, and the deployment of FPV grown because of competing land- designated walkways to allow access is accelerating worldwide. The first use pressures, renewable energy and for operation and maintenance. These commercial FPV installation came energy security goals, power sector connected floating platforms are online in 2007 at the Far Niente Winery resilience motivations, and other benefits anchored to the shore, to the bottom of in California, yet the vast majority associated with FPV. the water body, or to floating anchors. of existing systems have become The main electrical equipment resides operational since 2014 (Trapani and

1 Photo: FPV Installation in Tokushima, Japan. Photo by Adam Warren, NREL 50041 Redón Santafé 2015; Minamino 2016). 1,200 Global installed capacity has grown 1,097 from approximately 10 MW in 2014 to 1,000 near 1,100 MW by mid-2018 (Figure 1) (World Bank Group, ESMAP, and 800 Cumulative installed FPV capacity SERIS 2018). Primary markets include Japan and the United States; however, 600 Annual installed FPV capacity 585 FPV systems have been installed 512 throughout Southeast Asia, Europe, 400 453 and the Middle East. System sizes Installed Capacity (MWp) installed to date vary and range from 200 132 65 approximately 4 kW to 40 MW (Trapani 0 0 1 1 2 3 5 10 0 55 67 and Redón Santafé 2015; Sahu, Yadav, 1 2 2 5 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 and Sudhakar 2016; Mesbahi and Minamino 2018; Daley 2017). Figure 1. Global installed capacity of FPV in MW Source: World Bank Group, ESMAP, and SERIS 2018 Based on available surface area of artificial water bodies worldwide and system assumptions, the World Bank and the Solar Energy Research Institute of Singapore (SERIS) estimate global Box 1. Benefits of Floating Solar Photovoltaics Integration technical potential of FPV may range Utility-scale solar PV often requires significant parcels of land; however, from 400 GW to 1,000 GW. The FPV land-constrained developing countries may have to prioritize land use for market is expected to grow globally agricultural, forestry, or other needs. FPV may offer alternatives to scale from $13.8 million in 2015 to $2.7 up renewables and reduce competing land-use pressures by co-locating billion by 2025 (Grand View Research solar PV systems on artificial water bodies like reservoirs. In addition to 2017). Currently, FPV system costs generation, FPV may offer the following power system benefits, particularly (in terms of U.S. dollars per watt and when sited with existing hydropower: levelized cost of energy) are slightly higher than land-based equivalents • Avoiding land-energy conflicts • Power system benefits and (not including additional benefits of (e.g., energy versus food concerns reducing capital costs when FPV), but costs are expected to decline for land-use designation) co-located with hydropower (World Bank Group, ESMAP, and • Lowering land acquisition and • Reducing costs for waterbody SERIS 2018). site preparation costs maintenance due to decreased algae growth Research about the performance of • Gaining potential system FPV systems is nascent, but these efficiency and production due • Reducing rates of water systems have been of significant interest to temperature-regulating evaporation and increasing recently due to claims of benefits for effect of water; available water for other uses both water managers and power sector • Improving solar PV performance • Converting potentially underused stakeholders. The private sector leads due to reduced shading effects space into areas that allow for the development and deployment of revenue-generating use. • Increasing panel density for FPV technologies, with the research a given area (larger installed community showing increased interest. capacity per unit area) Still, many questions about FPV remain unanswered. Stakeholders need trusted, Sources: Hernandez et al. 2014; Hoffacker, Allen, and Hernandez 2017; Ibeke et al. 2017; Cazzaniga timely information to take advantage et al. 2018; Spencer et al. 2018Allen, and Hernandez 2017; Ibeke et al. 2017; Cazzaniga et al. 2018; of this emerging technology. This Spencer et al. 2018 leaves many potential opportunities for

2 Figure 2. Potential FPV Research and Analysis Topics

Analysis Implementation Monitoring and Technology Evaluation Research • How does FPV impact power • Identify FPV investment system operations, and what opportunities and technical • Monitor existing • Research and benefits does it provide? potential in a given area. systems to document development of system output built-for-purpose • What are the costs and • Conduct a techno-economic performance benefits. PV and supporting benefits of co-locating assessment of potential systems for FPV FPV with hydropower? projects using NREL’s • Validate and quantify the established methodology. environmental benefits • Explore FPV system • What tools can be of FPV related to reduced designs that reduce developed for FPV • Identify unique regulatory water evaporation and equipment weathering analysis, or how can and policy issues that need to reduced algal growth. and erosion. existing tools be used? be addressed for deployment. analysis, implementation, monitoring In addition to working domestically, References and evaluation, and technology research NREL is supporting countries around Cazzaniga, R., M. Cicu, M. Rosa- collaborations as shown in Figure 2. the globe with significant hydropower Clot, P. Rosa-Clot, G. M. Tina, and C. capacity and high-quality solar resources Ventura. 2018. “Floating Photovoltaic How Can We Collaborate on to advance development and use of Plants: Performance Analysis and renewable energy. This includes work Floating Solar Photovoltaics? Design Solutions.” Renewable and in Brazil, Colombia, Ghana, India, NREL has significant, internationally Sustainable Energy Reviews 81 Kazakhstan, Laos, Tajikistan, and renowned expertise in solar PV material (January): 1730-41. https://doi.org/ Vietnam, among others (NREL 2018; science, techno-economic analysis, 10.1016/j.rser.2017.05.269. USAID-NREL Partnership 2019). grid integration, and system design that Choi, Young-Kwan. 2014. “A Study it can bring to critical FPV research, The Future of Floating on Power Generation Analysis of analysis, and implementation questions. Floating PV System Considering For example, NREL researchers recently Solar Photovoltaics Environmental Impact.” International published a national assessment of the Continued work on FPV should Journal of Software Engineering and Its technical potential of FPV systems on advance an emerging global application Applications 8, no. 1: 75-84. https://doi. artificial water bodies in the United of solar PV and would offer multiple org/10.14257/ijseia.2014.8.1.07. States, establishing an adaptable benefits to stakeholders, such as methodology that could support similar diversity of generation, increased Choi, Young-Kwan, Nam-Hyung Lee, assessments worldwide. Through this investment opportunities, and and Kern-Joong Kim. 2013. “Empirical spatial approach, researchers identified economic development. Research on the Efficiency of Floating approximately 21,961 square kilometers PV Systems Compared with Overland of suitable man-made bodies of water Contact PV Systems.” In Proceedings, The 3rd for deployment that could potentially Samuel Booth International Conference on Circuits, support 2.1 terawatts of installed FPV National Renewable Energy Laboratory Control, Communication, Electricity, and produce an annual 786 terawatt- Tel: +1 303-275-4625 Electronics, Energy, System, Signal and Simulation, 25:284-289. hours of electricity (Spencer et al. 2018). Email: [email protected] In partnership with the Colorado Energy Daley, Jason. 2017. “China Turns on the Office and floating solar developer Written by Alexandra Aznar, Nathan Lee, World’s Largest Floating Solar Farm.” Ciel e Terre, NREL is evaluating FPV and Samuel Booth, National Renewable Smart News | Smithsonian. June 7, 2017. opportunities in Colorado. Energy Laboratory https://www.smithsonianmag.com/ smart-news/china-launches-largest- floating-solar-farm-180963587/.

3 Grand View Research. 2017. “Floating Krishnaveni, N, P Anbarasu, and Sahu, Alok, Neha Yadav, and K. Solar Panels Market Size & Share D. Vigneshkumar. 2016. “A Survey Sudhakar. 2016. “Floating Photovoltaic |Industry Report, 2018-2025.” https:// on Floating System.” Power Plant: A Review.” Renewable www.grandviewresearch.com/industry- International Journal of Current and Sustainable Energy Reviews 66 analysis/floating-solar-panels-market. Research and Modern Education. (December): 815-24. https://doi.org/ http://ijcrme.rdmodernresearch.com/ 10.1016/j.rser.2016.08.051. Hernandez, R. R., S. B. Easter, M. L. wp-content/uploads/2015/06/CP-024.pdf. Murphy-Mariscal, F. T. Maestre, M. Spencer, Robert S., Jordan Macknick, Tavassoli, E. B. Allen, C. W. Barrows, Mesbahi, Mina, and Saori Minamino. Alexandra Aznar, Adam Warren, and et al. 2014. “Environmental Impacts of 2018. “Solarplaza Top 70 Floating Solar Matthew O. Reese. 2018. “Floating Utility-Scale Solar Energy.” Renewable PV Plants.” January 3, 2018. https:// Photovoltaic Systems: Assessing the and Sustainable Energy Reviews 29 www.solarplaza.com/channels/top- Technical Potential of Photovoltaic (January): 766-79. https://doi.org/ 10s/11761/top-70-floating-solar- Systems on Man-Made Water Bodies 10.1016/j.rser.2013.08.041. pv-plants/. in the Continental United States.” Environmental Science & Technology, Hoffacker, Madison K., Michael F. Minamino, Saori. 2016. “Floating Solar December. https://doi.org/10.1021/acs. Allen, and Rebecca R. Hernandez. 2017. Plants: Niche Rising to the Surface?” est.8b04735. “Land-Sparing Opportunities for Solar Solar Asset Management: North in Agricultural America. November 11, 2016. Trapani, Kim, and Miguel Redón Landscapes: A Case Study of the Great https://solarassetmanagement.us/ Santafé. 2015. “A Review of Floating Central Valley, CA, United States.” news-source/floating-plants-article. Photovoltaic Installations: 2007–2013.” Environmental Science & Technology Progress in Photovoltaics: Research 51, no. 24: 14472-82. https://doi.org/ NREL. 2018. “International Activities: and Applications 23, no. 4: 524-32. 10.1021/acs.est.7b05110. Country Programs.” National Renewable https://doi.org/10.1002/pip.2466. Energy Laboratory (NREL). 2018. Ibeke, Mfon, Emily Miller, Dylan https://www.nrel.gov/international/ USAID-NREL Partnership. 2019. Sarkisian, Jessica Gold, Sydney country-programs.html. “Delivering Clean, Reliable, and Johnson, and Kester Wade. 2017. Affordable Power in the Developing “Floating Photovoltaics in California - Pickerel, Kelly. 2016. “What to Consider World.” National Renewable Energy Project Final Report | Tomkat.” August When Installing a Floating Solar Array.” Laboratory: USAID-NREL Partnership. 2017. https://tomkat.stanford.edu/ Solar Power World. June 13, 2016. 2019. https://www.nrel.gov/usaid- floating-photovoltaics-california-project- https://www.solarpowerworldonline. partnership/. final-report. com/2016/06/consider-installing- floating-solar-array/. World Bank Group, ESMAP, and IRENA. 2018. “Renewable Power SERIS. 2018. “Where Meets Generation Costs in 2017.” Abu Dhabi: Redón Santafé, Miguel, Juan Bautista Water: Floating Solar Market International Renewable Energy Torregrosa Soler, Francisco Javier Report - Executive Summary.” Agency (IRENA). http://irena.org/ Sánchez Romero, Pablo S. Ferrer 131291. The World Bank. http:// publications/2018/Jan/Renewable- Gisbert, José Javier Ferrán Gozálvez, documents.worldbank.org/curated/ power-generation-costs-in-2017. and Carlos M. Ferrer Gisbert. 2014. en/579941540407455831/Where-Sun- “Theoretical and Experimental Analysis Meets-Water-Floating-Solar-Market- of a Floating Photovoltaic Cover Report-Executive-Summary. for Water Irrigation Reservoirs.” Energy 67 (April): 246-55. https://doi.org/ 10.1016/j.energy.2014.01.083.

Samuel Booth NREL is a national laboratory of the U.S. Department of Energy National Renewable Energy Laboratory Office of Energy Efficiency and Renewable Energy 15013 Denver West Parkway Operated by the Alliance for Sustainable Energy, LLC Golden, CO 80401 Tel: +1 303-275-4625 NREL/TP-7A40-73907 • June 2019 Email: [email protected] NREL prints on paper that contains recycled content. www.nrel.gov