World’s largest seasonal energy storage site to be hosted in Finland

The world’s largest seasonal energy storage site will be hosted in Vantaa, Finland. Upon its completion in 2028, it will store 90 GWh of thermal energy.

The storage facility being built by Vantaa Energy will be over one million cubic meters in size and will contain 90 GWh of thermal energy, enough to meet the annual heating demand of a medium-sized city in Finland.

Three caverns roughly 20 meters wide, 300 meters long, and 40 meters high, all 100 meters below ground level, are set to be excavated to make way for the storage facility.

The aforementioned caverns will be filled with hot water, and pressure will be created within the space, whereby the water can reach up to 140 C in temperature without boiling or evaporating.

Jukka Toivonen, CEO of Vantaa Energy, explains, “The world is undergoing a huge energy transition. Wind and solar power have become vital technologies in the transition from fossil fuels to clean energy. The biggest challenge of the energy transition so far has been the inability to store these intermittent forms of energy for later use.”

Image: Vantaa Energy