Offshore Wind Power Projects in the Great Lakes - Ministry of ...

Offshore wind power projects in the Great Lakes: Background and science considerations for fish and fish habitat
5.5 Assessing the potential impacts of electromagnetic fields on fish
The potential impacts of EMFs from submarine power cables on fish behaviour and physiology
are poorly understood, especially in a Great Lakes setting. In order to fully understand or predict
the effect that emissions from submarine turbine cables will have on aquatic species, a valuable
piece of information is the nature and strength of the electric and magnetic fields associated with
the specific type of electrical transmission cabling to be employed at a given offshore wind
power installation. While electrical engineering models can be used to simulate or predict field
strengths and their attenuation with distance from the cabling, direct EMF measurements should
ideally be made in the field at varying distances from the cable, and across the full range of
voltages and amperages expected to be carried by the cables across their operational lifetime, and
as additional turbine units come online (U.S. Department of Energy 2009). Measurements should
be conducted not only along the length of the cable running to shore (where burial might occur to
greater depths in some areas and alter EMF strength) but also within the inter-turbine array. It
has recently been recognized that significant EMF interaction can occur between cables lying
within close proximity to each other within an offshore wind power project, such as would occur
at offshore substation connection points (Gill et al. 2005). The potential for additive effects from
overlapping EMFs is difficult to predict based on modelling alone and would need to be
analyzed through site-specific measurements of the resultant field strengths of multiple closely
arrayed cables.
Once measurements of EMF strengths are made in the field, they can be compared to the
reported electro- or magneto-sensitivity of different fish or benthic organisms likely to be found
within or travelling through the proposed project area. In this way, the likelihood that EMFs
from submarine cables could be detected by and potentially alter the movement or migration of
local fish species could be evaluated and best management practices put in place to reduce any
anticipated interference. Beyond this, seasonal baseline or pre-construction fish community
surveys throughout the project area and along the proposed cable route would be needed to
establish whether EMF-sensitive species inhabit or move throughout the area. In order to
definitively determine whether these species will be affected by EMFs from the submarine
power cables, however, field studies assessing the behavioural response of fish to the electric and
magnetic fields from the cables during wind turbine operation are necessary. The behavioural
response of local fish to EMFs could be elucidated by observing the reaction of individuals as
Aquatic Research and Development Section 64