Semco Maritime Moves From Design to Production on Stillstrom's Offshore Charging Control Unit

Stillstrom by Maersk has taken its offshore power and charging solution a step closer to operational deployment, signing a letter of intent with Semco Maritime to manufacture the local equipment room, the centralised control unit at the heart of the system.

The Unit That Runs the Entire Charging System

The local equipment room is a containerised unit purpose-built to govern every element of Stillstrom's offshore charging infrastructure. Power, communications and safety systems across the entire charging solution all connect through it and are managed by it. Inside the unit sit a transformer and medium voltage switchgear that carry offshore wind-generated power to a vessel, alongside communications equipment, ventilation and fire safety systems.

The unit is designed to be positioned on a monopile or hang-off structure at each individual charging site. Gordon Dickson, operations and maintenance lead at Stillstrom UK, left no ambiguity about the component's importance.

"The LER is extremely significant to our solutions as it acts as the nerve centre of our charging system. It controls everything that happens, from how power reaches the vessel to how every safety system talks to each other. Without it, nothing in the system moves," he said.

Dickson also noted that the design phase with Semco Maritime had shaped the unit around the practical demands of offshore installation and operations, adding that moving into manufacturing brought the company another step closer to demonstrating the complete charging solution in an operational environment.

Agreement Formalised at WindEnergy Hamburg

The letter of intent was signed on Wednesday, September 23, 2026, at WindEnergy Hamburg. The signing marks the transition from a completed design phase, which Semco Maritime carried out earlier this year, into active manufacturing.

Siemens has joined the effort in a subcontractor capacity to supply the switchgear and control systems, and a separate letter of intent between Semco Maritime and Siemens was also signed at the Hamburg event.

Stephen Booth, Vice President of Renewable Service at Semco Maritime, said the agreement built directly on the groundwork laid during the design phase. "This milestone reflects the strong collaboration we've built with Stillstrom through the design phase, and we're proud to carry that into manufacturing at our Esbjerg facility. And with Siemens joining as our subcontractor for the switchgear, we have the right partner to deliver on this next step together," Booth said.

Production Targeted for Esbjerg by Spring 2027

Manufacturing of the local equipment room is planned to take place at Semco Maritime's facility in Esbjerg, Denmark, with completion targeted for spring 2027.

The two companies have indicated that future production of the unit could potentially be supported from Semco Maritime's facilities in the United Kingdom, though no firm commitments on that point have been announced.

Semco Maritime's Earlier Role in Yard Trial

The manufacturing agreement is not Semco Maritime's first contribution to Stillstrom's development work. The company also supported an earlier yard trial in which

Stillstrom successfully demonstrated that its fully automated cable control can operate while a vessel is running on dynamic positioning. Semco Maritime's involvement in that trial included setting up the test from its Esbjerg facility.

Stillstrom's Background and Market Focus

Stillstrom was founded in 2019 as a Maersk innovation project and became an independent company in 2022. The company employs more than 30 people across offices in Copenhagen, Denmark, and Aberdeen, United Kingdom.

Its offshore wind charging technology is designed to be either fully integrated within wind farm structures or deployed through standalone offshore installations, enabling fully electric and hybrid service operation vessels to maintain low emissions during offshore wind operations by drawing on renewable electricity.

The company's commercial focus is on offshore wind markets in the UK and Europe.