Cowrie EMF

Each array of turbines at an offshore wind farm site will require a network of interconnecting cables and a cable link to land for connection to the national grid. This network of cables will generate electromagnetic fields (EMF) but these need to be quantified and reviewed in respect of the potential impact on electrosensitive species. The most widespread electrosensitive fish group in UK coastal waters are the elasmobranch fishes (i.e. sharks, skates and rays) which have electroreceptive organs and utilise electromagnetic fields for prey detection, orientation and navigation.

COWRIE (Collaborative Offshore Wind Research into the Environment) identified the issue of EMF generated by offshore windfarm power cables and their possible effect on organisms that are sensitive to these fields as a priority research area. Accordingly, a study was commissioned to begin appropriate scientific investigations and a consortium led by CMACS was contracted by COWRIE at the end of 2002 to undertake preliminary research.
The specific tasks the CMACS led team took on were:

to estimate the likely magnitude of EMF
to suggest a method to measure EMF in the field
to provide guidance on mitigation measures to reduce EMF
interpretation of results in terms of the effects of EMF on electrosensitive fish species.

The study included field measurements in the Clwyd estuary near Rhyl, North Wales using a portable probe developed by our colleagues at the University of Liverpool to measure in situ EMF. CMACS reported to COWRIE in July 2003 (CMACS Report). Further studies are planned to measure EMF at offshore locations and to investigate behavioural effects on electrosensitive fish species.