IN Brief:
- Wärtsilä and RCT Solutions will own the planned energy storage joint venture on a 50:50 basis.
- The business covers utility-scale BESS hardware, controls, optimisation software, and lifecycle support.
- The transaction reflects a storage market moving towards stronger integration, bankable support models, and tighter project economics.
Wärtsilä has agreed to move its global energy storage business into a 50:50 joint venture with German engineering company RCT Solutions GmbH, creating a new operating structure for one of the better-known names in utility-scale battery energy storage system integration.
Under the proposed arrangement, Wärtsilä will transfer its Energy Storage business into the jointly owned company. The division covers integrated BESS delivery, control systems, optimisation software, and lifecycle services, and reported net sales of €694m in 2025 with around 480 employees globally.
RCT Solutions brings engineering capability across solar and battery storage systems, including manufacturing facility development and global supply-chain execution. The company has also been a supplier to Wärtsilä Energy Storage for several years, giving the new structure an established technical and commercial connection from the outset.
The ownership split will be equal at closing, although the structure allows for new investors at a later stage. Wärtsilä will transfer net assets representing less than 5% of its total net assets into the company, with the transaction expected to close in the third quarter of 2026, subject to regulatory and customary approvals and the arrangement of financing.
Wärtsilä expects the new business to remain loss-making in 2026, driven by low recent order intake and transformation costs, including write-downs of capitalised research and development. The expected impact on the company’s 2026 operating result is between €40m and €50m, depending on the timing of completion, with positive results expected towards the end of 2027.
The deal also changes Wärtsilä’s reporting structure. Energy Storage will cease to be a separate reporting segment from the second quarter of 2026, while previous financial targets and demand guidance for the division will no longer apply. Until closing, the business will be treated as discontinued operations and assets held for sale.
Utility-scale storage is entering a more demanding commercial phase as project pipelines expand and procurement becomes more disciplined. Integrators are being judged on system availability, bankability, safety evidence, warranties, delivery certainty, and long-term service support, rather than only on headline megawatt-hour capacity.
Margins across BESS integration have tightened as cell supply chains shift, grid-code requirements become more complex, and developers expect more complete system guarantees. The early market tolerated bespoke project-by-project engineering, but larger deployment now rewards repeatable hardware platforms, reliable controls, clear service obligations, and strong supply-chain access.
Wärtsilä’s GEMS software and optimisation capability remain central to the storage proposition. Storage economics increasingly depend on cycling strategy, state-of-charge management, degradation modelling, trading optimisation, and participation across balancing, frequency response, congestion management, and renewable integration services.
The wider storage market is moving in the same direction, with manufacturers expanding containerised and medium-voltage storage architectures to reduce integration complexity. Hardware remains essential, but system value is now shaped by how effectively the equipment can be financed, installed, controlled, maintained, and operated across multiple revenue streams.
For RCT Solutions, the joint venture gives access to a larger global storage platform. For Wärtsilä, it reduces direct segment exposure while retaining a stake in a business that remains strategically linked to energy flexibility, grid stability, and renewable integration.
The new structure places the storage business in a more specialised vehicle at a point when the sector is moving from rapid market entry to industrial discipline. Utility-scale storage still has strong demand drivers, but the companies supplying it now need the same qualities expected from the assets themselves: tighter control, lower losses, reliable performance, and resilient long-term operation.
