Fortum and ST1 embark on a pilot project for geothermal production in Espoo


Energy companies Fortum and ST1 have entered into a collaboration to build Finland’s first industrial-scale geothermal pilot heat plant. ST1 will begin planning the pilot production plant, which is estimated to be completed in 2016. A construction site for ST1’s geothermal production plant is being looked for in the same area as Fortum’s Otaniemi and Kivenlahti heat plants. Fortum will buy the heat energy produced by the plant for Espoo’s district heating grid.

The geothermal plant is estimated to have a production capacity of up to 40 MW of geothermal energy. With that output, Fortum will be able to cover around 10% of the district heating needs in the Espoo region. Because no fuels are used in geothermal energy production, the plant will not generate any emissions into the atmosphere.

Geothermal energy is produced by drilling two holes several kilometres deep into the ground. Water is fed into one of the holes and as the water heats up in the ground, it rises through the other hole. In the geothermal plant, the hot water passes through a heat exchanger before entering the district heating grid. The water becomes so warm during the process that it can be used directly in district heat production without the need for heat pumps.