Charging a ship's batteries at sea has moved from simulation to tested hardware. Stillstrom by Maersk says it has completed construction and factory acceptance testing of its Vessel Container Unit (VCU), an 11 kV system for charging service operation vessels (SOVs) directly from offshore wind farms. DNV witnessed the tests. The company calls it the world's first 11 kV connection system of its kind.
How the unit works
- Containerised: the VCU houses an 11 kV connector package and can be installed at the bow, at the stern or beneath the deck.
- New and existing ships: it can be fitted to newbuilds or retrofitted to existing vessels. It can also be moved between vessels where onboard cabling permits.
- Charging at the right heading: an integrated funnel lets the vessel charge at an optimal heading. The dynamic positioning operator stays in control of charging and disconnection.
- Safety: OE Digital reports that the system includes control technology and safety interlocks designed for repeated offshore connections and disconnections.
«For vessel operators, charging at sea is no longer a concept. In simple terms, the VCU has been built and tested, and we are good to go,» said Graeme Wood, managing director of Stillstrom UK, as quoted by reNEWS.
Next steps
Work on the interface on the wind farm's topside structure is continuing. Stillstrom expects the complete charging system to be ready for extended offshore trials by summer 2027. Lessons from the prototype are feeding into a Mark 2 version, which would move the current semi-automatic alignment towards full automation.