Floating solar power as an alternative to hydropower expansion along China's Yellow River

Hydropower provides a growing renewable energy source, yet remains controversial due to its environmental impacts. We demonstrate a potential solution to hydropower growth that integrates solar power and hydropower by installing floating photovoltaic (PV) infrastructure at existing hydropower reservoirs. This solution circumvents new hydro-dam construction by supplying the same amount of energy from new floating solar power installations. We simulated this solution in the upper main stream of China's Yellow River, where 15 new hydro-dams are planned. We find that installing floating PV on 25.3 % of the existing hydropower reservoirs would provide enough energy to replace all new hydro-dam construction and save 497.1 km² of land compared to land-based PV replacement. Although floating PV as an alternative to hydropower expansion could slightly increase the initial investment (up to 9.0 %), it would avoid the adverse impacts hydropower poses to the Yellow River basin and alleviate land pressure for PV development.