Abstract
At the request of TRC Environmental Corporation (TRC), on behalf of US Wind Inc. (US Wind), Exponent calculated the alternating current electric and magnetic fields (EMF) associated with the operation of the Maryland Offshore Wind Project (the Project), an offshore wind energy project of up to approximately 2,000 megawatts of nameplate capacity within Lease Area OCS-A 0490. Electricity generated by offshore wind turbine generators (WTG) is proposed to be transmitted on Inter-array Cables to up to four Offshore Substations. Offshore submarine Export Cables would complete the connection to shore at a proposed landfall location at the 3R’s Beach in the Delaware Seashore State Park and then through Indian River Bay to the point of interconnection. This report summarizes the magnetic fields associated with the operation of the submarine transmission cables. Levels of EMF were calculated for the Inter-array Cables, Offshore Export Cables and Export Cables in Indian River Bay. These calculations were performed for two configurations: buried and beneath protective coverings. For purposes of this assessment, the Offshore Project Area is defined as the roughly 80,000-acre Lease Area where the Inter-array Cables, WTGs, and Offshore Substations will be installed, the Offshore Export Cable Corridor along which the Offshore Export Cables will be installed, and the Indian River Bay Export Cable Corridor. Magnetic fields at the seabed and at a height of 1 m above seabed in the vicinity of the buried cables were assessed for the peak electricity generation (i.e., all WTGs producing maximum power), and transitory exposures at this peak loading were found to be below reported threshold levels for effects on the behavior of magnetosensitive marine organisms. Electric fields induced in seawater and in local electrosensitive marine organisms were assessed in the same areas, and were similarly found to be below reported detection thresholds. For these reasons, as well as those discussed in greater detail in the body of the report, neither induced electric fields nor magnetic fields associated with the operation of the Project cables are expected to affect the populations or distributions of fishes in the Offshore Project Area. May 23, 2023 1602106.000 - 2976 viii Average magnetic- and induced electric-field exposure for the medium term (i.e., over hours and days) was calculated for limited regions adjacent to the mattress- or rock-covered cables, where certain fish species may spend more time than near buried cables. The volume-averaged, magnetic-field magnitudes were calculated over these limited regions, where some species may likely be present, and were determined to be far below threshold levels at which longer-term exposures have been reported to affect the behavior or physiology of certain fish species.