Understanding potential environmental impacts is a key issue in gaining acceptance of new technologies. Primary concerns relating to tidal stream turbine installations are interference with the local ecosystem during installation activities, the potential of the rotating blades to injure fish, diving birds and sea mammals during operation and the loss of amenity, fishing areas and navigation space for other users of the sea area.
As Evopod™ is a floating tethered device it imposes less disturbance on sensitive seabed ecosystems that bottom mounted structures and its unducted turbines coupled to a geared drive rotate at such low tip speeds that they are unlikely to be a threat to marine wild life. Nevertheless Oceanflow’s Sanda Sound project embodies an extensive pre and post installation environmental monitoring program in order to better add to the body of environmental impact knowledge and de-risk future projects.
The location of Oceanflow's E35-01 device in Sanda Sound was initially marked by a yellow special mark navigation buoy from September 2012. The device itself was deployed in August 2014 attached to the same moorings as the buoy and displays the same navigation light (flashing yellow all round at 5 second interval) and yellow St Andrews Cross on its mast and is marked as such on Admiralty Chart 2126.
Vessels can pass Evopod™ units just as they would pass a navigation buoy. Farms of Evopod™ units would involve creating an exclusion zone marked by four quadrant navigation buoys. Tidal turbines can be installed with much closer spacing than wind turbines and typically a one square kilometre of sea area in a location such as the Pentland Firth could deliver enough energy to support 40,000 homes. This would reduce carbon dioxide emissions by 140,000 tonnes per annum, if replacing power from a coal-fired power station.