An international study coordinated by the Belgian Research Institute for Agricultural, Fisheries and Food Research (ILVO) and led by the Federal Maritime and Hydrographic Agency (BSH) and the French Research Institute for Exploitation of the Sea (Ifremer) shows that offshore wind farms could potentially release over 200 chemical substances into the sea. How can these substances be better detected, assessed, and regulated? Initial technical solutions and regulations to reduce these emissions already exist. Internationally, Germany is playing a pioneering role in this area. However, there is a lack of coordination across Europe.

The international research team conducted a literature review and used research articles, former literature reviews, reports, and material safety data sheets to identify 228 chemical substances that offshore wind farms could potentially release. These mainly include substances from corrosion protection systems (70 percent) as well as oils and lubricants (10 percent) that are necessary for operation. Other potential emissions, such as those from cooling agents and fire extinguishing agents, are also included.

The majority of the chemical substances belong to the group of organic compounds (64 percent), followed by inorganic compounds (19 percent). Of the 228 substances identified, 62 are considered particularly relevant to the environment. This is because they are on priority lists, for example, from the European Chemicals Agency or under the European Water Framework Directive, which assesses substances according to their impact on the environment.

These may be substances that are potentially toxic, persistent, endocrine-disrupting, carcinogenic, or can be accumulated in the food chain. However, more research is necessary to determine the actual amount of substances released from offshore wind farms and what kind of impact these emissions have on the marine environment. This will be key to ensuring the protection of the oceans and their sustainable use.

How Much Comes from Where?

But how can such emissions be monitored in practice? The diversity of substances and their use in other areas on land and at sea make it difficult to clearly attribute the impact of offshore wind farms. Complex analysis is therefore necessary to determine where the substances mainly come from, how much actually enters the marine environment, and what effects they have.

Dr. Pablo Zapata Corella from IFREMER said: “In order to obtain reliable data on these potentially released substances, we need state-of-the-art analytical methods that achieve very low detection limits. In addition, tracing pollution sources in environments with many potential emission sources requires further research, as it is quite complex.”

One option is to measure the concentrations of some selected substances before the construction and during the operation of offshore wind farms in order to identify any changes. Modeling can also help to better understand the distribution and behavior of the substances in the environment. However, there are currently no standardized procedures for monitoring the emitted substances.

Available But Not Mandatory

With the increasing spread of offshore wind energy, it is crucial to monitor chemical emissions and investigate their impact on the marine environment. At the same time, these emissions should be reduced by using more environmentally friendly materials and techniques.

The study also shows that some emissions may be technically avoidable, for example, through alternative corrosion protection systems, closed cooling systems, or biodegradable operating materials. However, there are no industry-specific standards such as those used in shipping. The study recommends binding technical guidelines that should apply to the approval and operation of offshore wind farms.

National Regulations Exist, But Not Internationally

The study also compares how the US, the UK, and Germany regulate chemical emissions from offshore wind farms. The approaches vary greatly, and there is currently no comprehensive regulation. In the US and the UK, the authorities assess environmental aspects during the approval process, taking into account potentially released chemicals. Internationally, Germany is playing a pioneering role in this area.

Project developers must submit an emissions concept to BSH during the planning phase in Germany, describing potential material inputs and measures to prevent or reduce them. Approval is followed by a detailed emissions study. Waste and operating material concepts are also required and must be updated regularly.

The BSH sets binding technical and environmental requirements for offshore projects, for example on waste disposal, corrosion protection, wastewater management and the use of cooling or extinguishing systems. For example, zinc-based anodes for corrosion protection are prohibited in German marine waters, as are biocide-containing coatings to control biofouling.

In France, offshore wind farms are subject to regulatory monitoring of the chemical quality of the water and the biofouling of submerged structures.

Closer Integration of Research and Practice

Such guidelines should apply not only nationally but also internationally, as chemical emissions from offshore wind farms spread across borders into the marine environment. Various stakeholders should also be involved at an early stage in order to implement the guidelines quickly.

The study was conducted as part of the European Interreg project Anemoi, together with the Marine Chemistry and Offshore Renewable Energy working groups of the International Council for the Exploration of the Sea (ICES). In the future, the study could serve as a basis to strengthen cooperation between researchers, operators, and regulatory authorities.

Dr. Elena Hengstmann from BSH emphasized: “Our literature study provides an important basis for the early detection of chemical emissions from offshore wind farms. Europe-wide coordination and minimum requirements for monitoring and reduction can make the necessary expansion of offshore wind energy more environmentally friendly.” This will protect both the climate and the marine environment.