The materials used to protect wind turbines from corrosion leach into the surrounding water, which could pose risks to ecosystems, seafood safety and human health, new research from the University of Portsmouth has found.

Offshore wind farms release thousands of tonnes of metals such as aluminium, zinc and indium each year. This is expected to grow dramatically as wind farms are set to play a major role in reducing the world’s carbon emissions.

The UK currently has 13 gigawatts of offshore wind power generating capacity and a government target of reaching 100 gigawatts by 2050.

Professor Gordon Watson, from the University’s School of the Environment and Life Sciences, said: “Offshore wind farms are a vital part of our clean energy future, but at the moment there is limited data on how these metals affect the environment near operational offshore wind farms, so it’s hard to assess the full risks.

“We are definitely not saying stop building offshore wind farms, we just need to monitor them appropriately - especially as they continue to expand. The plans to scale up are ambitious and come with challenges that must be addressed.”

To protect turbines from rusting, corrosion-protection systems are used, which can release metals into the ocean over time.

The study, published in Nature’s npj Ocean Sustainability, estimated annual inputs of metals from current European wind farms to be:

• 3,219 tonnes of aluminum

• 1,148 tonnes of zinc

• 1.9 tonnes of indium

For zinc, this already exceeds the sum of all known direct inputs and river discharges into the North Atlantic from key European countries.

Locating seaweed and shellfish farms in close proximity to offshore wind farms, like the world’s first co-located commercial-scale seaweed farm in the North Sea, could see metals from turbines build up in these species, leading to concentrations that could exceed safe limits for human consumption.

For example, consuming oysters with high levels of zinc could surpass the recommended weekly intake for adults, posing risks to human health.

Professor Watson added: “Under current government expansion plans, these inputs could increase 12-fold by 2050, which raises serious concerns about the potential accumulation of metals in marine species like oysters, mussels, and seaweed, which are also likely to be cultured near wind farms.

“Our research highlights the importance of keeping a close eye on the chemicals released by offshore wind farms, so we can monitor and manage the environmental impact.”

The scientists are calling for more comprehensive monitoring of water and sediments around wind farms, using corrosion-protection systems with fewer environmental impacts, and strong monitoring guidelines for co-locating aquaculture with wind farms.

Professor Watson said: “There are solutions to address these issues, but we need to take steps now to mitigate risks. We hope this research will provide a roadmap for policymakers and the wind energy industry to tackle these challenges effectively before they cause unnecessary harm.”

The research was a collaboration between the University of Portsmouth’s Institute of Marine Sciences and the Plymouth Marine Laboratory.

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