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The Combined Power of Floating Solar on Hydro Reservoirs Shows New Potential

Isabelle Branco-Lo
Oct 27, 2020

Guidehouse Insights

In October 2020, Norwegian PV developer Scatec Solar announced its plans to acquire hydropower developer SN Power from the Norwegian government for $1.17 billion. It is not unusual for renewable developers to diversify assets and operations, but the timing of this deal may be more than serendipitous. Just a month earlier, the US National Renewable Energy Laboratory (NREL) released a report concluding that floating solar panels deployed on existing hydro reservoirs could generate anywhere from 16%-40% of the world’s energy needs. One of the few examples of a system operating with this technology is the Alto Rabagão Photovoltaic Park in Portugal, which has 840 solar panels on the Alto Rabagão hydroelectric station.

Synergetic Potential in Developing Regions

While floating PV (FPV) is 10%-15% higher in upfront capital costs and per-kilowatt cost compared to conventional PV, FPV used in conjunction with hydropower provides a host of other benefits. These include reduced transmission costs by linking to a common substation, reduced evaporation, reduced algae growth on hydro reservoirs, and increased efficiency of panels due to its water-cooling effect.

Perhaps the most compelling advantage of FPV on existing hydro dams is the possibility for 24/7 dispatchable power, as the floating solar panels can bridge the demand gap that hydro power cannot fill during dry seasons. This is especially applicable in Latin America and South Asia. It is estimated that Brazil’s existing hydropower facilities have underproduced by approximately 12 GW due to severe droughts in recent years. As a result, Brazil is currently working to expand a 1 MW floating solar planet on the Sobradinho Dam to 5 MW. Companhia Hidroelétrica do São Francisco has also installed a pilot 10 MW floating PV array on the Balbina Dam.

Opportunities Float Ahead

Despite the apparent advantages of FPV plus hydro, the FPV market applies to all bodies of water. According to The World Bank’s 2018 report, Where Sun Meets Water: Floating Solar Market, installed capacity of FPV has grown from below 1 MW in 2007 up to 1.13 GW in 2018. It has a global potential of 400 GW in 2020. FPV is largely driven by Asia Pacific, especially in Japan where the first installation occurred in back in 2007, and in China. In Europe, large projects are being developed in Belgium and the Netherlands. According to an NREL study from 2018, in the US, floating solar on man-made bodies of water alone could provide about 10% of the country’s power needs. Duke Energy announced that it will install floating solar panels totaling 1.1 MW in Fort Bragg, North Carolina, the largest military facility in the world, as part of its $36 billion energy and water conservation plan.

Hydropower accounts for nearly 60% of the global renewable mix, and solar is the fastest growing renewable energy source. As long as these technologies continue to lead, floating solar may play an important role for the future of energy.