Consideration of scales in offshore wind environmental impact assessments

Quality of environmental impact assessments (EIAs) has been criticized, in part due to a lack of accounting in these tools for differing spatial and temporal scales inherent in ecological data. In the United States, leases of outer continental shelf blocks for offshore wind projects and their construction and operation plans require EIAs in accordance with the National Environmental Policy Act of 1969 and the 1978 Council on Environmental Quality Regulations for Implementing the Procedural Provisions of the National Environmental Policy Act. This study evaluated consideration of spatiotemporal scales of stressors, receptors (specifically cetaceans), and effects in eight federal offshore wind energy EIAs against 26 criteria extracted from federal regulations. The criteria analysis determined that EIAs do not consistently or comprehensively address spatiotemporal scales with respect to federal requirements. Deficiencies in addressing spatiotemporal scales may result from imprecise regulations, intent to simplify encyclopedic documents, or lack of data resulting in incomplete assessments, inappropriate mitigation actions, and projects delays. Recommendations to improve compliance with federal regulations include making federal guidance binding, focusing on non-trivial impacts of species, tiering information, and incorporating outcomes of marine spatial planning.