total of three caverns about 20 meters wide, 300 meters long and 40 meters high will be excavated
bottom of the caverns will be 100 meters below ground level
underground caverns will be filled with hot water
Pressure will be created within the space, allowing the water to reach temperatures of up to 140 degrees without the water boiling or evaporating
total volume is 1,100,000 cubic meters, including process facilities
fully charged seasonal thermal energy storage is 90 gigawatt-hour, could heat a medium-sized Finnish city for as long as a year
Two 60-MW electric boilers will be built in conjunction with Varanto. These boilers will be used to produce heat from renewable electricity when electricity is abundant and cheap
project cost is estimated to be around 200 million euros, and it has already been awarded a 19-million-euro investment grant from Finland’s Ministry of Economic Affairs and Employment. Construction of the storage facility
could be operational in 2028