FlatEMF 

Electromagnetic fields (EMFs) are a combination of electric and magnetic fields of force, produced either naturally or through human activities. With the large-scale deployment of offshore renewable energy projects, both current and planned, the interest in understanding EMFs in the marine environment has grown.  

Offshore energy infrastructure includes inter-array and export cables, which are associated with the presence of EMFs in marine ecosystems. While power cables are typically buried in the seabed or protected with concrete mattresses, EMFs can still be detected in the surrounding environment. Some cables also remain exposed in the water column, particularly in floating wind farms, or cannot be fully buried due to local seabed conditions.  

To improve knowledge on this topic and support fact-based discussions among all sea users, 50Hertz, Europacable, EirGrid, the Renewables Grid Initiative and TenneT have joined forces to conduct and commission studies on EMFs in relation to commercially important flatfish species, specifically European flounder (Platichthys flesus). 

What were the project’s objectives? 

Impacts of electromagnetic fields on flatfish behaviour 

Laboratory research was carried out by St Abbs Marine Station which showed no evidence of attraction, avoidance, or erratic behaviour, indicating a no stress response to EMF. However, when exposed to EMF, the day/night circadian rhythm of flounder activity in an aquarium was altered. Further research is required to better understand the possible cause of results seen in this study and whether they occur out in the field as well. 

Based on these results, no further mitigation measures were investigated; rather, the recommendation is to focus on cable burial depth, bundling and (micro)routing. 

EMF calculation guidelines 

To assess the EMF intensity of future land and offshore projects, EMF modelling guidelines were created based on the literature. These guidelines were then tested against data collected from a monitoring station and data collected in-situ around a subsea cable.