Wärtsilä has agreed to establish a joint venture with German company RCT Solutions  for its global Energy Storage business. The ownership structure of the joint venture will be 50% RCT Solutions and 50% Wärtsilä. At a later stage, new investors may join the joint venture, which could reduce the ownership of the initial shareholders.

The joint venture would include Wärtsilä’s Energy Storage business currently reported as a separate segment. The Energy Storage business has been the smallest segment within Wärtsilä, with about 480 employees globally and net sales of EUR 694 million with a profitability of 3.3% in 2025. Wärtsilä would transfer net assets representing less than 5% of Wärtsilä’s total net assets into the joint venture.

Wärtsilä’s Energy Storage business supports the decarbonisation of the energy market by delivering utility-scale integrated battery energy storage systems (BESS) and optimisation with proven reliability, flexibility, and safety. The portfolio includes high-performance hardware, intelligent controls and optimisation software, and full-service lifecycle support.

RCT Solutions GmbH is a German engineering company, founded in 2012, with strong international expertise in solar and battery energy storage systems (BESS). RCT Solutions brings strong market knowhow, business execution capability, knowledge of the global supply chain, as well as an opportunity for vertical integration through an existing integrated BESS manufacturing initiative in the USA in the near term. RCT 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.

“After closing the transaction of the joint venture, Wärtsilä will be partnering with an experienced player with strong capabilities in operating an integrated energy storage business in challenging market conditions. RCT Solutions has the aim to develop into a global vertically integrated battery energy storage system player. This transaction offers an excellent opportunity for the Wärtsilä Energy Storage business to strengthen its competitiveness,” says Håkan Agnevall, President & CEO, Wärtsilä.

“This joint venture is a significant step in building a stronger, more competitive global energy storage platform. By combining Wärtsilä’s proven technology, customer base and project expertise with RCT Solutions’ engineering capabilities, vertical integration knowhow and existing manufacturing initiative in the USA, we are creating a foundation to succeed in the rapidly evolving energy storage market. Our focus will be on strengthening competitiveness, accelerating profitable growth, and positioning the joint venture as a leading player in battery energy storage worldwide. Furthermore, I am delighted to take up the role of CEO of this new joint venture after the closing of the transaction”, says Peter Fath, CEO, RCT Solutions GmbH.

Closing of the transaction is expected in the third quarter of 2026 subject to regulatory and other customary conditions and approvals as well as arrangement of a financing package. As a result of the agreement, in the second quarter of 2026, Energy Storage will cease to be a separate reporting segment, the financial targets for the business will no longer apply, and demand guidance will be suspended. The transaction is expected to have no material profit and loss impact at closing. The joint venture will benefit from the project guarantees already issued by Wärtsilä regarding the ongoing projects.

The joint venture is expected to be loss-making in 2026 driven by recent low order intake as well as costs related to transformation actions, consisting mainly of write-down of capitalized R&D. The impact to Wärtsilä’s full year 2026 operating result is estimated to be EUR -40 to -50 million depending upon exact timing of closing.

The joint venture is expected to generate positive results towards the end of 2027.

Until closing of the transaction, the Energy Storage business will be reported as Discontinued Operations and Assets Held for Sale. From the closing date onwards, Wärtsilä will report the joint venture under Other Business Activities as share of result in associated companies.

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