Vantaan Energia to build 90GWh energy storage facility in Finland

April 23, 2024

Vantaan Energia has announced plans to build a €200 million seasonal thermal energy storage facility in Vantaa, Finland’s fourth largest city, which is near the capital of Helsinki.

When completed, the 90GWh seasonal energy storage facility will be the “largest in the world by all standards”, said a Vantaan Energia statement.

The seasonal thermal energy storage system, called Varanto, will store heat in underground caverns that can be used to heat buildings via the district heating network.

In Finland and other Nordic countries, heat consumption varies significantly between seasons. Heat consumption in summer is only about one-tenth of the peak load consumption during the cold winter months. The possibility to store cheap and environmental friendly waste heat from data centres, cooling processes and waste-to-energy assets in underground caverns is a “revolutionary innovation in terms of the energy transition”, the statement said.

The facility will be built in Vantaa’s bedrock, where a total of three caverns about 20 meters wide, 300 meters long and 40 meters high will be excavated. The bottom of the caverns will be 100 meters below ground level. These 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.

The total volume of the caverns will be 1,100,000 cubic meters, including process facilities. The facility at Varanto will be almost as large as two Madison Square Gardens, the New York city indoor arena.

Vantaan Energia CEO Jukka Toivonen said: “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. Unfortunately, small-scale storage solutions, such as batteries or accumulators, are not sufficient; large, industrial-scale storage solutions are needed. Varanto is an excellent example of this, and we are happy to set an example for the rest of the world.”