Dirt cheap backup

Sand batteries can ensure round-the-year availability of clean energy

- SEEMA PRASAD

FINLAND HAS installed the world’s first sand battery that can store heat from renewable energy sources for months. The Finnish developers told Down To Earth that the battery, made of sand collected from construction sites, can solve the problem of round-the year energy supply, a known limitation of renewable energy sources that can be harnessed intermittently. This is a major breakthrough, as heat alone accounts for half of the world’s energy use, followed by transport (30 per cent) and electricity (20 per cent), as per intergovernmental organisation International Energy Agency (iea). Currently, 80 per cent of the world’s energy comes from dirty fossil fuels.

The battery, a massive steel silo, 7 m tall and 4 m wide with 100 tonnes of sand, was installed in Finland’s Kankaanpää town in June 2022. It is connected to the town's centralised heating network that keeps buildings and public water systems warm. Owing to the cold temperature, all municipalities and cities in Finland have centralised heating networks, and 70 percent of them use renewable sources, as per non-profit The Finnish District Heating and Cooling Association.