Wind farm in rough seas

Compressed air that is made using energy from North Sea wind farms (above) could be stowed in the aquifers under the seafloor. Credit: Paul Glendell/Construction Photography/Avalon/Getty

Renewable energy

Aquifers could store enough energy to power a nation for months

Compressed air made with renewable energy could be stashed in underground deposits for lean times.

Saltwater aquifers could store renewable energy for long periods, providing a means to generate electricity when sun and wind power lag.

Utilities generally store energy by pumping water into the reservoirs above hydroelectric dams for later release. Julien Mouli-Castillo at the University of Edinburgh, UK, and his colleagues analysed brine-filled rock formations known as saline aquifers to determine whether they could provide long-term storage of compressed air. During seasons when renewable energy runs short, the air could be released to drive a turbine and generate electricity.

Focusing on potential storage sites close to the United Kingdom, the team calculated that saline aquifers below the North Sea could store up to 96 terawatt hours of electricity. That’s enough to meet the entire UK electricity demand for January and February of 2017.

The authors suggest that their methodology could be used to estimate the storage potential of similar aquifers in other regions.