A lithium-ion battery said to be the biggest in the Nordic countries was installed in conjunction with Fortum’s biomass-fired power plant in Järvenpää, Finland. The EUR 1.6 million (USD 1.6 million) Batcave project, housed in a construction container, uses technology by French battery maker Saft Groupe SA.

The Batcave battery. Source: FortumThe 2 MW/1 MWh battery storage system includes 6,600 lithium-ion cells, offering second- and minute-level grid flexibility in frequency regulation.

Take a video tour of the Batcave.

The combined heat and power plant utilizes biofuels to produce district heat for about 34,000 residents in the Tuusula and Järvenpää communities, as well as electricity for the national grid. The plant produces about 280 GWh of heat and about 130 GWh of electricity annually. Biofuels include locally sourced forest residues, forest industry by-products, and animal manure.