Planned wind farms in the Bay of Bothnia are expected to affect winter navigation. The question is: to what extent? And will the plans need to be adjusted? A pre-study conducted by the Swedish Transport Administration and Lighthouse has begun investigating these issues.

“There are several planned wind farms in the Bay of Bothnia that have not yet been approved. Before that happens, a strategy should be developed to determine how they can best be positioned to minimize their impact on shipping,” says Vasiola Zhaka of Uppsala University, one of the researchers behind the pre-study Potential Impacts of Wind Farms on Shipping in the Bay of Bothnia, carried out within the Swedish Transport Administration’s industry programme Sustainable Shipping, which is managed by Lighthouse.

New fixed structures at sea will naturally affect shipping operations, particularly during winter. They not only constitute physical obstacles but may also alter local ice conditions, including ice concentration, ice thickness, and ice drift. This raises concerns that they could restrict the flexible route-selection system coordinated by the icebreaking service and contribute to increased operational risks.

So how often and to what extent do the planned wind farms overlap with winter shipping routes? And how do these overlaps change under different levels of winter severity?

“Using AIS data, we reconstructed vessel routes and combined them with ice data from different winters. The results show that the planned wind farms and shipping routes overlap in several locations. To understand the challenges this may create, we interviewed icebreaker captains, who indicated that available manoeuvring space will be reduced, especially in severe ice conditions. This could, for example, make convoy operations—where icebreakers lead several vessels—more difficult. Ships may also become trapped in ice without icebreakers being able to reach and assist them.”

Could the research findings lead to changes in the location or design of the wind farms?

“The first and most fundamental measure is to adapt the design of the wind farms. However, in this pre-study we have not proposed any specific changes to their location or design. That will be addressed in the next project, which is also funded by Lighthouse. In that project, we also plan to develop an AI-enhanced digital twin of vessel traffic to identify optimal routes while supporting real-time icebreaking operations. The goal is to minimize conflicts so that both shipping and wind power can operate efficiently side by side. This is important. Rapid industrial development in northern Sweden is not only driving increased demand for electricity—forecasts also indicate that the number of vessels operating in the area could triple compared with today,” says Xiao Lang of Chalmers University of Technology, who also participated in the pre-study.

Potential Impacts of Wind Farms on Shipping in the Bay of Bothnia was authored by:
Xiao Lang, Wengang Mao and Jonas W. Ringsberg (Chalmers University of Technology)
Vasiola Zhaka (Uppsala University)
Niklas Hammarkvist (Swedish Maritime Administration)

In collaboration with
Frida Åberg (Swedish Agency for Marine and Water Management)
Niklas Broman (Skyborn Renewables)