Potential biological impacts of very low frequency acoustical energy produced by offshore wind turbine energy generation

Abstract

Offshore wind turbine farms are being planned and installed around the US Outer Continental Shelf. These will be introducing a panoply of noises into the environment, from siting, through installation, to operations, and eventually decommissioning. Noise concerns from these activities are typically framed within frequency bands of concern defined by governmental regulatory agencies. A less considered noise is the very low frequency thump generated by the motion of the turbine blades as they intersect the “stagnate wind area” on the windward side of the mast. This “infrasonic” thump contains a lot of energy and is in the perceptual range of migratory birds and baleen whales. Given that whales and birds use “infrasonic” sound and barometric pressure signals for navigation and migration cues, the installation of thousands of turbines off the Atlantic Outer Continental Shelf, and hundreds off the Pacific OCS, may impose significant impacts on migratory passerine birds along the “Atlantic Flyway,” Procellariiformes on both the Atlantic and Pacific OCS, and all baleen whales within the infrasonic energy propagation reach of the turbines.