They are called “floatovoltaics” – photovoltaic cells that are mounted on buoys that are set afloat on a water surface. When linked to a reservoir, this concept offers several advantages.

There is no need to purchase premises to operate them on, and installation is easy. The U.S. Department of Energy’s National Renewable Energy Laboratory has issued a study that shows the potential behind the concept. Up to 10,600 TWh of energy could be generated if floatovoltaics were to be implemented world­wide on existing hydropower reservoirs. Compare this to the global annual energy consumption in 2018, which was 24,700 TWh. By combining on-site hydro and solar power, any excess solar energy generated this way could be utilised for pumping water from lower levels up to higher elevated reservoirs. Overnight the water could then be discharged again to drive turbines for energy production. Best of all, the entire infrastructure for feeding the solar energy to the grid exists already.