Plans for the world’s biggest offshore wind farm, 55 miles off the coast of Yorkshire have been thrown into doubt over fears the noise of building it will disturb porpoises. A decision on planning permission for Dong Energy’s 1.8 gigawatt Hornsea Two project, which would see up to 300 giant turbines had been due from the Department of Energy and Climate Change soon but the decision has been delayed after the Department for Environment, Food and Rural Affairs proposed designating a vast, 14,000 square mile tranche of the North Sea – including the entire 115 square mile area of the proposed wind farm – as a Special Area of Conservation (SAC) for the harbour porpoise. Designating areas as SACs is designed to ensure this status is maintained by avoiding “deterioration of the habitats of the harbour porpoise or significant disturbance to the harbour porpoise”. It is well known that this particular species of cetacean are sensitive to impulsive noise from activities such as pile driving and as a result, a Habitats Regulations Assessment must now be carried out to look at “the likely significant effects of the project, both alone and in-combination with other plans and projects” on the porpoise protection zone.
Although there are a range of mitigation measures available that could potentially reduce the noise footprint of the project to acceptable levels this could potentially require significant changes to the proposed construction of the wind farm, such as seasonal restrictions on turbine installation.Dong Energy said it already implemented mitigation measures to protect marine mammals, such as “using trained observers to ensure that the area around the offshore construction site is clear of marine mammals before any piling work starts”. The harbour porpoise is the smallest and most prevalent marine mammal in UK waters.