Federal reservoirs in the US offer a technical potential of up to 1.042 TW DC floating solar capacity that can generate up to 1,476 TWh clean energy, enough to power close to 100 million homes every year, according to a study conducted by the National Renewable Energy Laboratory (NREL). Potential floating photovoltaic generation capacity on these reservoirs is estimated to be in the range of 861 GW DC to 1,042 GW DC depending on input assumptions, potentially representing approximately half of future US solar generation needs for a decarbonized grid. The study, titled Floating photovoltaic technical potential: A novel geospatial approach on federally controlled reservoirs in the United States, believes that even in the conservative estimates, these reservoirs could host projects with capacities of up to 77 GW. “That’s a technical potential,” explained NREL Geospatial scientist Evan Rosenlieb while referring to the 1,476 TWh technical potential of floating solar in the US. “We know we’re not going to be able to develop all of this. But even if you could develop 10% of what we identified, that would go a long way.” At present, the US does not have a single floating solar project over 10 MW capacity, points out NREL. Nevertheless, it is for the 1st time, says NREL, that the researchers have used the most detailed criteria including water depth and temperature along with factoring in legal and regulatory perspectives to quantify the amount of energy that can be generated from floating solar panel projects installed on federally owned or regulated reservoirs. This study differs from previous studies that focused more on how much energy can be generated from floating solar panels, but NREL researchers were the first to consider the factors that ensure the best conditions for a floating solar power plant location using their novel spatially explicit methodology. According to the researchers, the spatially explicit criteria used in this study show the developable area of a reservoir expressed as a percent of the total area can vary widely, depending on site-specific factors for each reservoir. This highlights the shortcomings of methods that assume a flat percentage of reservoir area as developable and the need for continued work to refine these efforts. They say the most ideal locations for these floating solar power plants are hydropower reservoirs since these will work as hybrid energy systems with both hydropower and solar energy generation providing more resilience to the grid. At the same time, in times of drought, solar panels can generate electricity while the reservoir get replenished. Another opportune location can be new pumped storage hydropower projects that are being built, leading to the creation of new water bodies that are disconnected from naturally flowing rivers and are not home to any animals. The accuracy provided by the study can help developers more easily plan projects on US reservoirs and better assess how these technologies fit into the country’s broader energy goals, says the NREL. Future iterations of the study will also review the locations closer to transmission lines or electricity demand, cost and also navigating federal and state regulations. Other potential locations including smaller reservoirs, estuaries, and ocean sites will also be the subject of discussion. Funded by the Solar Energy Technologies Office and the Water Power Technologies Office in the US Department of Energy’s Office of Energy Efficiency and Renewable Energy (EERE), the study has been published in the Solar Energy journal.
