Offshore wind energy is to be massively expanded by 2030. In the course of the expansion in the North Sea, the environmental impacts will be monitored regarding the effect of novel habitat introduction, underwater noise or the exclusion of fisheries. However, the potential chemical contamination with dissolved and particulate pollutants from the wind turbines, e.g. from the corrosion protection systems, remains largely unknown. This is where the Anemoi project, which is funded through the Interreg North Sea Programme and in which the Technische Universität Braunschweig is also involved, comes in. Within the Anemoi project, researchers from 11 European institutes will work in close collaboration with policy makers and the OWF industry. A first stakeholder meeting is planned on 30 and 31 May 2023 in Hamburg, Germany.

Chemicals enter the marine environment through numerous land-based sources, related to industry, traffic or households, and activities at sea like shipping, mariculture, dredging and offshore energy.

In the upcoming four years (2023-‘27), 11 European institutes will investigate the occurrence and impacts of chemical emissions from offshore wind farms (OWFs) in the North Sea. Wind turbine foundations contain corrosion protection systems, which leach metals such as aluminium or zinc into the sea. Paints on the turbines leach organic compounds into the water, while the paint can crack and flake from the turbines by wave motions, and plastic particles can be torn down from the turbine blades.

What effects do chemical emissions have on marine life?

Within Anemoi, an Interreg North Sea project, the emission, concentration and distribution of known and unknown chemical compounds in the water and sediments will be identified by means of field monitoring and lab experiments (e.g. by mimicking particle distribution in a wave flume system).

Secondly, the impact of chemical leachates from OWFs on marine life and different aquaculture products will be assessed through ecotoxicology studies and risk assessments, and the effects at different trophic levels will be modelled for both single and mixed chemical compounds.

Proposal for a single legal framework in the North Sea Region

Thirdly, different regulations are currently in place at the national and European levels to limit the impact of chemical emissions from OWFs. To further reduce the potential impact, the different regulations within the North Sea region will be reviewed and an aligned regulatory framework will be proposed. Finally, Anemoi will investigate sustainable and non-harmful solutions (e.g. alternative corrosion protection systems) and optimizations to further reduce chemical emissions from OWFs.

Experiments in the wave-current flume of LWI

The Department Hydromechanics, Coastal and Ocean Engineering of the Leichtweiß-Institute for Hydraulic Engineering and Water Resources (LWI) at TU Braunschweig is specifically investigating the behaviour of macroscopic paint particles from the corrosion protection layer of offshore wind turbines under wave loads as part of the Anemoi project. To this end, the scientists are first developing methods to realistically reproduce the paint particles and their detachment behaviour on a model scale. Subsequently, far-reaching investigations will be carried out in the LWI’s wave-current flume.

“Understanding the flow and sinking behaviour of paint particles allows important conclusions to be drawn about the extent of the environmental impact of offshore wind turbines. The experiments conducted at the LWI provide data on this that was previously unavailable,”

says project member Dr Christian Windt.

To reach the project goals, Anemoi will work in close collaboration and interaction with the offshore wind farm sector and with policymakers. A first stakeholder event is foreseen on 30 and 31 May 2023 in Hamburg (Germany), to exchange knowledge on the effects and risks of chemical emissions from OWFs and to discuss potential solutions to further increase the sustainability of offshore wind energy.

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