Offshore wind farms are expanding fast. By the end of 2024, more than 80 gigawatts of capacity will be installed worldwide. These vast structures promise clean energy and reduced reliance on fossil fuels.
But scientists warn that they may also leak dangerous chemicals into the sea.
A review by an international team, published in the Marine Pollution Bulletin, found that offshore wind farms (OWFs) could release more than 200 different organic and inorganic substances into marine waters.
These range from metals and plastics to industrial chemicals used in paints and protective coatings.
Where the Chemicals Come From
The main culprits are coatings on steel structures. These protective paints, often made from polyurethane or epoxy, contain additives like bisphenols, phenols, and solvents.
Over time, sunlight, saltwater, and physical wear break them down. This process can release both micro-particles and dissolved chemicals.
Sacrificial anodes—blocks of metal designed to corrode instead of the turbine’s steel—are another source. They slowly release aluminium, zinc, and sometimes toxic metals like cadmium, lead, and mercury.
Other emissions come from oils and greases, firefighting foams, and even the slow erosion of rotor blades.
Unknowns in the Water
Despite these risks, chemical pollution from wind farms has been little studied. The authors note that regulators have focused more on noise, habitat changes, and bird collisions. In many countries, there are no standard requirements to monitor chemical releases from OWFs.
Some of the identified substances are on official “priority hazard” lists, meaning they are known to be toxic, persistent, or able to build up in the food chain. For example, bisphenol A is linked to hormone disruption in wildlife and humans.
The review warns that these chemicals could enter seafood, including shellfish grown in aquaculture zones inside or near wind farms. This could create risks for both marine life and people.
Measuring the Invisible
Tracking these pollutants is technically challenging. The chemicals occur in low concentrations and are easily diluted in seawater. Some sink into sediments; others travel long distances in the water or air.
The scientists recommend a risk-based monitoring approach—focusing on the most harmful and likely pollutants. They suggest combining field sampling, laboratory tests, and computer models to understand how chemicals move and accumulate.
The review also highlights the need to study the combined effects of different chemicals. Metals and organic pollutants may interact, creating more severe impacts than when studied alone.
A Call for Stronger Rules
Although some countries have basic rules to reduce emissions, the authors say there is no consistent international standard. They argue for a “fit-for-purpose” regulatory framework that accounts for chemical pollution alongside other environmental impacts.
Offshore wind energy remains a key part of the climate solution. But, as this study shows, its green image comes with a chemical footprint that must be better understood and managed.