North Sea Wind Farm Expansion May Shift Rain Away From the Coast, Simulations Suggest

Offshore wind farms are a key pillar of the energy transition, and the European Union plans to expand offshore wind capacity in the North Sea by 2050. A new study by the Helmholtz-Zentrum Hereon, published in the journal Communications Earth & Environment, indicates that a very extensive expansion could influence regional precipitation patterns: while precipitation over the sea could increase, it could decrease in coastal regions.

Researchers at Hereon's Institute of Coastal Systems used the high-resolution regional climate model COSMO-CLM to simulate offshore wind expansion scenarios in the North Sea and Baltic Sea, based on a decade of weather data from 2008 to 2017, which let them identify potential long-term effects while reducing the influence of year-to-year variability. The scenario modeled was deliberately extreme — a purely technical expansion pathway assuming maximum deployment across all areas designated for potential offshore wind development, resulting in installed capacity substantially exceeding the currently discussed target of 300 GW by 2050 — chosen to make potential climate effects clearly detectable. "Our work helps ensure that the further expansion of offshore wind energy in Europe can be aligned with the requirements of climate protection, environmental protection and coastal management," said Dr. Naveed Akhtar, the study's lead author.

The simulations show that wind turbines extract part of the wind's kinetic energy and increase atmospheric turbulence, which downstream of the turbines enhances the exchange between different layers of the atmosphere, causing moist air to rise, cool and condense into clouds and rain over the wind farms. At the same time, this alters the transport of moisture toward the coast: if air masses release more of their moisture as precipitation over the wind farm areas, less remains available for precipitation on land.

For parts of Denmark, Germany, the Netherlands and the United Kingdom, the simulations indicate potential reductions in coastal precipitation of up to 15%. The findings reflect long-term weather statistics rather than individual weather events, and the researchers say they can support sustainable maritime spatial planning and cross-border cooperation in the North Sea and Baltic Sea region. Future research will examine a range of expansion scenarios and how factors such as turbine density, wind farm size and spatial distribution affect regional climate, as well as the impacts of offshore wind farms on the ocean and marine ecosystems.