There is also one of these in Västerås, Sweden, about 100 km from Stockholm. 3 caverns 30 m below the surface that used to store oil during the Cold War in case

There is also one of these in Västerås, Sweden, about 100 km from Stockholm. 3 caverns 30 m below the surface that used to store oil during the Cold War in case shit would hit the fan. 300,000 cubic meters, 13 GWh. Basically identical. Not as far along as the Finnish site though; it'll start backing up the district heating plant in 2024.