Reviewed by Lexie CornerJan 15 2025
A study published in Solar Energy by geospatial scientists Evan Rosenlieb and Marie Rivers, along with senior legal and regulatory analyst Aaron Levine, all from the U.S. Department of Energy's National Renewable Energy Laboratory (NREL), explored the potential of federal reservoirs to support the nation’s solar energy needs.
The team assessed, for the first time, the energy generation potential of floating solar panel installations on federally owned or regulated reservoirs.
Their findings revealed significant potential: reservoirs could accommodate floating solar panels capable of generating up to 1,476 terawatt-hours annually, sufficient to power nearly 100 million households.
That is a technical potential.
Evan Rosenlieb, Researcher III-Geospatial Science, National Renewable Energy Laboratory
The estimate represents the maximum energy generation potential if each reservoir were fully utilized for floating solar panel installations.
Rosenlieb added, “We know we are 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.”
Levine and Rosenlieb have yet to examine how human and wildlife activities might impact the development of floating solar energy on specific reservoirs, an issue they plan to address in future research.
This study provides a more accurate assessment of the potential for floating solar power in the United States. The improved accuracy could assist developers in planning projects on U.S. reservoirs and help researchers evaluate how these technologies align with the country’s broader energy goals.
Floating solar panels, or floating PV, offer several advantages: they generate electricity without competing for limited land resources and provide shading that cools water bodies, reducing evaporation and conserving critical water supplies.
But we have not seen any large-scale installations, like at a large reservoir. In the United States, we do not have a single project over 10 megawatts.
Aaron Levine, Senior Legal and Regulatory Analyst, National Renewable Energy Laboratory
Previous studies have estimated the potential energy generation from floating solar panels in the U.S., but Levine and Rosenlieb are the first to evaluate which water sources offer optimal conditions for such installations.
Certain reservoirs pose challenges for floating solar development. Shipping traffic can create wakes that damage mooring lines or disrupt floating infrastructure. Some reservoirs are too cold, too shallow, or have steeply sloped bottoms unsuitable for supporting solar panels.
However, some hydropower reservoirs could be suitable locations for floating solar power plants. A hybrid energy system that combines solar and hydropower could deliver more stable and robust energy to the power grid. If, for example, a drought depletes a hydropower station’s reservoir, solar panels could create energy while the facility waits for the water to replenish.
Additionally, some developers create entirely new reservoirs for pumped storage hydropower plants, which transfer water between reservoirs at different elevations to store and generate energy on demand. These reservoirs are not yet used for recreation, habitat, or food production and are disconnected from natural river systems.
Future research will examine which sites are near transmission lines or power demand, the potential costs of development at particular places, if a site should be avoided to preserve the local environment, and how developers might comply with local, state, and federal regulations. The team also aims to evaluate additional potential sites, including smaller reservoirs, estuaries, and ocean locations.
DOE’s Office of Energy Efficiency and Renewable Energy (EERE) funded the study through its Water Power Technologies Office and Solar Energy Technologies Office.
Journal Reference:
Rosenlieb, E. et. al. (2025) Floating photovoltaic technical potential: A novel geospatial approach on federally controlled reservoirs in the United States. Solar Energy. doi.org/10.1016/j.solener.2024.113177