Spanish island builds ‘giant water battery’ to boost energy security

Gran Canaria is perhaps best known for its sandy beaches, eternal sunshine, and volcanic past. But isolated far from the European mainland, the island relies heavily on imported fossil fuels to power its growing economy — 76% of its electricity comes from burning oil. 

In an effort to decarbonise, the government has been investing heavily in renewable energies to harness the island’s abundant wind and solar resources. In 2022, renewables made up 24% of the island’s energy mix, up from just 12% in 2018. But as more renewables come online, the island faces another problem: storage.   

Last year, the government invested €400m in the Canary Islands’ first-ever energy storage scheme, to stabilise the grid when the wind isn’t blowing or the sun isn’t shining. This project won’t build battery packs, however, but convert two existing dams into one giant water battery.

Salto de Chira, as the ‘pumped hydro’ project is known, will pump water from the Soria dam into the Chira dam — which sits at a higher elevation — during periods of low energy demand. During periods of high energy demand, water will be released from Chira, down a tunnel, over a set of turbines, and back into Soria. And the cycle continues.