Offshore wind farms are typically comprised of turbines, whose rotors convert mechanical energy from wind into electrical energy, and an offshore substation, which are linked to each other by a network of electrical cables. The electricity is transported onshore via export cables (which are typically buried in the seafloor) so that the energy can be integrated into the electrical grid. Turbines can either have fixed foundations, in which the foundation is driven into the seabed, or floating foundations, which have a series of anchors attached to the foundation via mooring lines. Floating turbine designs are newer and are generally deployed in much deeper waters (50-300 m, or 164-984 ft). For more detailed information and scientific citations, please see the full FAQ document linked below.

The primary factors associated with offshore wind development that may affect whales include underwater sound, vessel activities, and habitat change. Offshore wind development introduces a variety of sounds into the environment, particularly during wind farm construction, as well as additional boat traffic during construction, operations, and maintenance activities. In addition, offshore wind development could lead to changes in the habitats, which may result in either positive (e.g., artificial reef creation) or negative change (e.g., effective habitat loss). The potential impacts to individuals and populations from each of these changes will depend on multiple factors, including behavior, life history, population size, and habitat use. For more detailed information and scientific citations, please see the full FAQ document linked below.

There is no documented scientific evidence that offshore wind energy activities kill whales. While offshore wind energy development, like any marine development, has the potential to affect whales (see What are the potential effects of offshore wind development on whales?), the sounds produced during all phases (i.e., site assessment, construction, and operations) are insufficient to cause direct mortality. However, the sound emitted may impact hearing or behavior, and cumulation of sounds from anthropogenic sources may lead to chronic effects. There are various mitigation measures in place to reduce risk of potential impacts (see What mitigation measures are being required by regulators in the U.S. for offshore wind?) Collisions are a concern for all vessels in the marine environment across industries. Vessel collisions have the potential to injure or kill whales. However, offshore wind vessels comprise a very small portion of all vessels in the marine environment, and they operate in a more precautionary manner to avoid the types of collisions that occur with other industries, which reduces this risk (see What mitigation measures are being required by regulators in the U.S. for offshore wind?). For more detailed information and scientific citations, please see the full FAQ document linked below.

Sources of anthropogenic sound include vessels, offshore wind energy development, oil and gas exploration, military exercises, and other activities, all of which have the potential to affect marine mammals to varying degrees. Some anthropogenic sounds are high-intensity and acute (i.e., occur for short durations), while other types of sound are lower-level and chronic (i.e., occur consistently). Sound varies in intensity, frequency, and duration; all of these characteristics influence the potential for sound to affect marine mammals. For more information, see What are the effects of anthropogenic sound on marine mammals? Sounds produced in relation to offshore wind energy development vary by phase (e.g., site assessment, construction, operations, decommissioning). Some chronic sounds are lower intensity (“volume”) and are nearly continuous (e.g., operational turbine sound). Other offshore wind-related sounds are high-intensity and acute (e.g., pile driving of turbine foundations into the seabed). Offshore wind energy construction, marine oil and gas exploration, military sonar, and vessel activities all produce substantial amounts of underwater sound, but they differ in their intensity and frequency and therefore potential effects on marine mammals. For more detailed information and scientific citations, please see the full FAQ document linked below.