Offshore wind farms could be used as charging hubs for electric and hybrid ships

Two Danish companies are exploring the possibility of integrating offshore wind with marine electrification – essentially positing the deployment of charging infrastructure for battery powered vessels at offshore wind farms.

Stillstrom, a spin-out from Danish shipping and logistics company A.P. Moller Maersk Group, is a marine technology leader delivering offshore power and charging solutions, which describes its mission on its website as reducing “vessel-related greenhouse gas emissions by enabling offshore charging and ensuring that battery powered vessels have access to uninterrupted power supply while anchored.”

The company claims that their offshore power and charging technology is capable of acting as “an offshore charging point to hybrid and electric vessels, or as a reduced emissions anchorage zone to the thousands of vessels idling outside of ports on any given day.”

In order to demonstrate the promise of its technology, Strillstrom announced on Tuesday that it would partner with the Port of Roenne, on the Danish island of Bornholm, to author a joint white paper exploring how offshore wind could be integrated with maritime electrification.

The new study, Energy Island Bornholm Powering Maritime Electrification, which is expected to be published in the first quarter of 2026, will aim to examine how renewable power production and future grid capacity can support charging solutions for electric ferries, cargo vessels and offshore service vessels.

Specifically, the white paper will centre its premise on the development of marine charging facilities as part of the envisioned Bornholm Energy Island, and how this integration could serve as a potential blueprint and scalable roadmap for ports and offshore hubs preparing for the next wave of maritime electrification.

Bornholm, a Danish island off the east of Denmark in the southern portion of the Baltic Sea, was designated in 2020 as central to one of two so-called “energy islands” the government of Denmark has committed to build by 2030.

The natural island is also central to one of the busiest shipping corridors in Europe – given its location central to not only Denmark, but Sweden, Finland, Estonia, Latvia, Lithuania, Poland, and Germany.

Choosing to centre an energy island at Bornholm was also bolstered by existing plans to use the island as a natural interconnection point between Poland and Denmark, making the decision to gradually build up offshore wind farms on the surrounding sandbanks a natural expansion of those plans.

As of writing, the Danish Government has approved Danish national transmission system operator Energinet to procure the transmission infrastructure for the planned energy island but has yet to decide on whether to auction the 3 GW offshore wind farm. Current plans for the Bornholm Energy Island envision two offshore wind farms, a HVDC converter station on Bornholm, and connecting cables to the mainland.

The Bornholm Energy Island is one of two under development, with the second located in the North Sea off the western coast of Denmark.

Both energy islands could play host to 3-gigawatts (GW) of offshore wind capacity – and in the case of the North Sea energy island, as much as 10 GW in the future, or more. And each “energy island” – a natural island, in the case of Bornholm, and an artificial island, in the planning for the North Sea project – would serve as the hub through which all the offshore power would travel to shore.

Stillstrom estimates that around 17 terawatt-hours (TWh) of new electricity consumption will one day be required to charge battery-powered vessels, which would in turn replace approximately 3 million mega tonnes of marine gas oil, saving roughly €2 billion in oil imports.

Image Credit: Stillstrom

“Maritime electrification is the next frontier of Europe’s green transition,” said Sune Strøm, Stillstrom’s senior regulatory & public affairs manager.

“But for shipowners to invest in battery-powered vessels, charging infrastructure must be built ahead of demand – both offshore and in ports.

“Energy Island Bornholm offers a unique opportunity to demonstrate how offshore wind energy can support vessel charging in one of Europe’s busiest shipping corridors.”

The Port of Roenne, as a Trans-European Transport Network (TEN-T) Comprehensive port, believes it is well placed to contribute practical insights into the types of infrastructure that may be required as maritime operations begin moving toward electrification – including those for future ferry charging, clean shore power for cruise vessels, and offshore charging.

“Energy Island Bornholm gives us a valuable opportunity to better understand what future maritime energy needs might look like,” said Jeppe La Cour, CCO of Port of Roenne.

“Our contribution to this collaboration is to share operational insights and explore how different charging scenarios could work in practice. With our central location in the Baltic Sea, we see a natural role in helping to qualify the discussion about what will be required to support the wider transition.”