Wärtsilä, the Finland-based technology group, is to establish a 50-50 joint venture with German engineering firm RCT Solutions for its global energy storage business.

Wärtsilä confirmed the deal on June 15, saying that new investors may join the joint venture at a later stage, which could reduce the ownership of the initial shareholders.

The new enterprise will include the Wärtsilä Energy Storage business, which is currently reported as a separate segment. The unit has been the smallest segment within Wärtsilä, with about 480 employees globally, net sales of €694 million ($796 million) and a profitability of 3.3% in 2025.

Wärtsilä said it will transfer net assets representing less than 5% of its total net assets into the joint venture.

RCT Solutions is a German engineering company, founded in 2012, with international expertise in solar and BESS. The company has led the engineering and establishment of several battery and solar manufacturing facilities worldwide, while one of the RCT companies has supported Wärtsilä Energy Storage as a key supplier for several years.

“This transaction offers an excellent opportunity for the Wärtsilä Energy Storage business to strengthen its competitiveness,” said Håkan Agnevall, president and CEO of Wärtsilä.

Peter Fath, CEO of RCT Solutions, who will become CEO of the joint venture, said: “By combining Wärtsilä’s proven technology, customer base and project expertise with RCT’s engineering capabilities, vertical integration knowhow and existing manufacturing initiative in the US, we are creating a foundation to succeed in the rapidly evolving energy storage market.

Closing of the transaction is expected in the third quarter of 2026 subject to various regulatory approvals and arrangement of a financing package.