RWE Investigates Impact of Artificial Reefs at Baltic Sea Offshore Wind Farms

By Editor


RWE, a leading player in offshore wind energy, is exploring how artificial reefs at offshore wind farms in the Baltic Sea can influence the marine ecosystem and create attractive habitats for species such as blue mussels, algae, and various fish.

In collaboration with Linnaeus University and cable service provider Baltic Offshore Kalmar AB, RWE has launched a pilot study in the Swedish Baltic Sea. Following extensive preparations, water sampling, and seabed assessments, the project has progressed to its practical phase with the installation of artificial reefs at RWE’s Karehamn wind farm. The wind farm, located 7 km off the Swedish coast, consists of 16 turbines with a total capacity of 48 MW.

A total of 180 carbon-neutral, plastic-free reef cubes, designed and manufactured by ARC Marine, have been deployed on the seabed. This deployment aims to evaluate how marine life colonizes these structures. The study, which commenced in 2023, is expected to continue until 2026. ARC Marine, a supplier of nature-inclusive solutions, received RWE’s “Innovation Ecology Award” in 2022.

The primary goal of the Kårehamn biodiversity pilot study is to assess how artificial structures at offshore wind farms can promote biodiversity and support ecosystem services such as habitat provision, nutrient cycling, and water quality, thereby contributing to the restoration and preservation of the Baltic Sea.

The initial phase of the study involved establishing a baseline scenario through underwater surveys and sampling, including eDNA sampling to assess the local ecosystem and identify species in the region. This data helps predict the potential impacts of the project phases and aids in effective planning.

The installation phase involved submerging 180 reef cube structures of various sizes, ranging from 15×15 cm to 75×75 cm, on the seabed at the Karehamn wind farm. This location was chosen due to the observed development of species on the wind turbine foundations, aiming to create artificial reefs that provide habitats and hiding places for macroalgae, blue mussels, and fish species.

From 2024 to 2026, the colonization phase will involve closely monitoring the submerged cubes and the surrounding ecosystem. This phase will yield valuable data and insights for the sustainable design of future offshore wind projects.

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