Japanese engineering firm Nippon Koei Co. Ltd. is forming a joint venture with U.K.-based RNA Energy Ltd. to build electricity storage projects in Britain.

Initially, the two companies agreed to invest approximately £25.1 million to construct two separate 50-MW battery storage projects. Nippon's Netherlands subsidiary Nippon Koei Energy Europe will have an 80% stake in the joint venture, while the remaining 20% will be held by RNA Energy.

The joint venture's name and location is yet to be determined, according to a news release. The financing will close by June 30.

The Nippon subsidiary said it expects to gather engineering, procurement and construction funds for providing related services for the two projects. The financing will close by June 30.

RNA Energy develops smart storage projects that deliver grid balancing services and behind the meter solutions to industrial users. The company currently has more than 200 MW of operating renewable energy assets in the U.K.