Chemical Emissions from Offshore Wind in the North Sea, or, Needles in a Needlestack

The marine environment is and will continue to be subject to major changes as an area of interest in the transition to renewable sources of energy. Offshore wind farms are springing up throughout Europe and the world, with EU targets projecting 60 GW by 2030 and 300 GW by 2050. Further commercial and regulatory interests target the addition of additional marine renewables strategies to existing offshore wind energy construction goals, further increasing the variety of structures and technologies introduced to the oceans. Not only structures or industrial activities themselves lead to emissions, but also forms of protection (particularly galvanic anodes, meant to protect large steel structures from corrosion). Lacking is exact knowledge of how emissions from offshore renewable structures interact with and accumulate in their environment. Furthermore, existing uses and historical pollution of coastal areas in combination with a naturally variable, dynamic environment.

This investigation makes use of nearly a decade of data from offshore wind farms and nearby sites in the North Sea, primarily conducting an analysis of metal mass fractions in the fine fraction (< 20 µm) of sampled sediments. Related analyses on seawater and biota are or will become available for reference. Established ICP-MS/MS methods have been used, with focus on technologically critical elements and elements considered by previous publications to have potential as tracers for offshore emissions. These include the galvanic anode components Zn, Ga, In, and Pb. Additionally, the method allows for analysis of over 50 elements. Statistical analyses of the data are complicated by environmental considerations: high natural variability of many elements, historical sources of pollution such as the element Pb, and active simultaneous inputs of contaminants such as Zn from other sources mask signals from the offshore structures under investigation.

These new data and their analysis are of value to understand effects on the marine environment in the context of planned acceleration of renewable energy generation strategies. As installations of offshore wind farms and other offshore renewables infrastructure intensify across Europe and the world, the potential to cause unintended environmental impacts grows along with them. Supported by national and internationally funded projects, the investigation presented here aims to explore the magnitude and ecological consequences of chemical emissions from offshore structures with the goal of informing policy and industry decision-making.