Offshore Wind and New Hampshire's Environment
The changing climate is rapidly affecting the Gulf of Maine. Warming water, ocean acidification, sea level rise, and more powerful storms are increasingly affecting the region. Offshore wind development in the Gulf of Maine has the potential to reduce emissions of greenhouse gases that drive climate change. Reducing our contribution to climate change will have long-term benefits for human health and the planet’s ecosystems, including marine ecosystems. However, there are potential environmental risks for marine and coastal ecosystems near offshore wind developments.
A general overview of potential environmental benefits and impacts of offshore wind development in the Gulf of Maine is provided below.
Offshore wind is a low-carbon renewable energy source that can help reduce greenhouse gas emissions.
The State of New Hampshire is already experiencing the effects of a changing climate. Since 1970, the State’s average annual temperature has increased by almost 3 degrees Fahrenheit. With a warming rate of 0.11°F per year, the Gulf of Maine has warmed faster than 99 percent of the global ocean over the past three decades. In the past decade, the State has also observed more frequent and extreme storm surges and precipitation events than usual which have increased financial losses and insurance costs. Relative sea level has risen approximately 7.5 – 8.0 inches in coastal New Hampshire over the past century and is expected to continue rising for centuries to come. These effects of climate change impact ecosystem function and human health in many ways.
Reducing our reliance on fossil fuel energy sources and curbing greenhouse gas emissions are essential to slow the acceleration of damaging consequences of further climate change globally and in New Hampshire. Shifting some of New Hampshire’s energy supply to offshore wind energy can help contribute to greenhouse gas reduction and provide a low-cost, domestic energy supply for the state.
Outside of construction and maintenance considerations, the operation of wind turbines generates no carbon dioxide (CO2) emissions. Offshore of Massachusetts, the Vineyard Wind project is expected to prevent 1.68 million metric tons of CO2 emissions annually, once operational. This is equivalent to taking over 300,000 cars off the road. Deploying enough offshore wind capacity to reach a national goal of 30 gigawatts of offshore wind would reduce U.S. carbon dioxide (CO2) emissions by 78 million metric tons per year.
With some of the strongest and most consistent wind resources in the world, the Gulf of Maine can contribute to the national capacity of offshore wind to provide clean renewable energy. Governor Sununu signed an executive order calling on the Office of Strategic Initiatives (OSI, now the Department of Energy), the Department of Environmental Services (DES), and the Department of Business and Economic Affairs (BEA) to study and report on the greenhouse gas reduction potential of offshore wind in the Gulf of Maine.
Offshore wind can help reduce local air pollution, improve air quality, and protect human health.
The fossil fuels that drive climate change are also major sources of harmful air pollution. Fossil fuel combustion releases six of the most common health-harming air pollutants: carbon monoxide, lead, ground-level ozone, particulate matter, nitrogen dioxide, and sulfur dioxide. These pollutants affect lung and heart health and can cause cardiovascular disease, respiratory diseases like asthma and emphysema, and cancer.
In New Hampshire, the primary source of air pollution is fossil fuel combustion from the state’s transportation sector, including combustion from cars, trucks, buses, trains, and airplanes. The New Hampshire Commission to Study Environmentally-Triggered Chronic Illness was formed in 2019 to study environmental illnesses and diseases in New Hampshire, including health issues linked to air pollution.
Because the operation of offshore wind turbines is emission and pollution free, offshore wind energy will be critical to meet New Hampshire’s demand for clean electricity sources. Clean electricity generated from offshore wind, coupled with other technologies like the electrification of the transportation sector, can help reduce local air pollution, improve air quality, and protect human health.
Map of fossil fuel power plants in New England overlaid with the region's respiratory health index percentile. This mapping tool was created at Northeastern University's School of Public Policy and Urban Affairs in partnership with the Environmental League of Massachusetts. Learn more here.
Electricity produced from offshore wind requires less water inputs than electricity produced from conventional sources.
Unlike conventional electricity sources, electricity generated from wind turbines requires almost no water inputs. Conventional electricity is produced using a thermoelectric process. This process, which converts energy from coal, oil, gas, or nuclear sources into electricity, is highly water intensive. In 2015, thermoelectric power plants in the US consumed 133 billion gallons of water, or 40% of the country’s total water use, per day. This means that in 2015, each kilowatt-hour (kWh) of electricity produced in the U.S. required an average of 15 gallons of water.
Because wind turbines generate electricity directly from power harnessed from the wind, the water intensive process of thermoelectric generation is not required. Shifting some of our state’s energy supply to offshore wind energy can help meet our growing demand for electricity while protecting the region’s water supply.
Marine and Coastal Ecosystems and Offshore Wind
The Gulf of Maine provides habitat for over 3,300 species of marine plants and animals, including many federally protected threatened and endangered species. Minimizing impacts on the diverse marine ecosystems of the Gulf of Maine during the construction, operation and decommissioning of offshore wind projects is an important part of responsible offshore wind development. Choose a topic or scroll down to learn more about potential impacts of offshore wind on marine and coastal ecosystems.
Changes to the Seafloor
Installation of offshore wind turbines and transmission cables will cause disturbance to the seafloor, or benthic zone. The benthic zone is important habitat for many fish, coral, and invertebrate species that use it for food, refuge, and spawning (reproduction). Turbine foundations can disturb benthic habitat and cause changes to natural communities near the wind farms. A three-year study of benthic habitat within the Block Island Wind Farm found that sediments near turbine foundations shifted from coarse sands to muddy sands enriched with organic material. Scientists also found that turbine foundations acted as an artificial reef bed and observed new aggregations of mussels and bivalves. Studies of floating turbines deployed off the coast of Scotland confirm that floating turbine infrastructure also supports artificial reefs. Further studies are underway to study the artificial reef effect in the Gulf of Maine.
Photos from an environmental survey report performed by Equinor at Hywind Scotland, the first commercial wind farm that employs floating wind turbines, illustrate the artificial reef effect on underwater turbine infrastructure.
Left: Nudibranchs (Aeolidia papillosa) and barnacles (Balanoidea) at 48 m depth on floating turbine substructures
Right: Epifauna colonizing floating turbine mooring line
Turbine foundations can also affect the benthic zone by changing nearby water currents. Satellite imagery shows that offshore turbines can create wakes with high levels of suspended sediments. These types of local changes in hydrodynamic and sedimentary processes may be especially disruptive to species, including many fish species, that have a larval life stage. Upwelling of currents may attract fish, and seabirds that feed on them.
The turbine’s foundation, as well as the methods used anchor the turbine, determine its environmental impact. Because Gulf of Maine waters deepen to over 100 meters within a few miles from shore, it is likely that floating turbines will be used instead of fixed-bottom turbines. Floating turbines have a smaller footprint on the seafloor than fixed bottom foundation and have fewer direct impacts on benthic species and habitats.
Because transmission cables are buried under the seafloor, or covered with concrete mattresses when the seafloor cannot be trenched, their installation will also cause disturbance to the seafloor and sediment suspension in the short-term. Cable-laying and particle settlement was also studied by BOEM during the construction of the Block Island Wind Farm.
Disturbance to Bird and Bat Habitat
Bird and bat species use coastal and offshore habitats during migration and foraging activities. Studies conducted by BOEM indicate that there is significant offshore bird activity as well as bat activity on the Atlantic Outer Continental Shelf.
Offshore wind turbines, like onshore wind turbines, can cause mortality as well as displacement of birds and bats. Bird and bat mortality caused by land-based wind farms in the United States has been well-documented. Many studies have examined the potential vulnerability of bird species to offshore wind energy projects on the Atlantic Outer Continental Shelf, including a study lead by the researchers at the Maine-based Biodiversity Research Institute and the University of Massachusetts, which examines cumulative impacts of multiple offshore wind farms on bird habitat. Further research is still needed to identify critical habitat and migratory hotspots in the Gulf of Maine specifically.
Siting of offshore wind turbines will be key in minimizing bird and bat mortality and displacement. Learn more about the research BOEM is doing to evaluate the interactions between coastal bird and bats and offshore wind energy here.
Mark Olsen, Eastern Egg Rock, Saint George, Maine
Underwater Acoustic Impacts
The deployment of offshore wind turbines generates underwater noise. Research on the offshore wind farm construction and other ocean activities, including military exercises and seismic surveys for offshore oil reserves, shows that anthropogenic noise can have negative impacts on marine species. Marine mammals and fish, and to a lesser extent, sea turtles and invertebrates, all show sensitivity to underwater anthropogenic noises.
The overall impact that anthropogenic noise may have on a given species is determined by noise levels, the duration of noise, distance from noise source, and the auditory sensitivity of the species. may change their behavior to avoid loud noise sources and become displaced from critical feeding grounds or migratory routes. Pressure and vibration associated with extremely loud noises may also cause death or serious injury, particularly in fish and marine mammal species that have specialized organs that amplify sound.
Measuring a baseline record of bioacoustics and anthropogenic noise can help marine scientists evaluate the impacts of noise created during offshore wind development construction. BOEM has funded multiple baseline studies of marine soundscapes in areas of the Atlantic Outer Continental Shelf that may be suitable for offshore wind development.
Most underwater noise associated with offshore wind energy is generated during the installation, rather than the operation, of wind turbines. The majority of offshore wind turbines installed to date are fixed-bottom turbines with monopile foundations. Monopile foundations are deployed by driving deep columns into the seabed, a process called pile driving. Most research on the acoustic impacts of offshore wind has focused on noise generated during pile driving for monopile foundations.
Right Whale, Credit: NOAA Fisheries
Underwater anthropogenic noise can cause the masking of other ocean sounds, like the communications of marine mammals.
Marine mammals, like the North Atlantic right whale, rely heavily on sound for communication. Listen to sounds of the North Atlantic right whale recorded by NOAA.
Masking of communications can interfere with foraging, predator avoidance, and social activities.
Because the Gulf of Maine is very deep, it is likely that floating turbines will be used instead of fixed-bottom turbines with monopile foundations. fixed-bottom turbines, floating turbines may require pile driving during installation. However, the installation of floating turbines o generate less noise overall. Because floating turbines are still an emerging technology, further research is needed to characterize the acoustic impact of their installation.
Mitigation measures, including curtailing construction activities during certain months of the year or using quieting technologies to reduce underwater noise, may be used to protect marine life during offshore wind development. For example, Vineyard Wind has identified several mitigation measures they will take to reduce the impact of noise on North Atlantic right whales during the construction of Vineyard Wind Project off the coast of Massachusetts.
Risk of Vessel Strikes from Increased Vessel Traffic
Collision with boats and ships is a leading cause of death for sea turtles and marine mammals, including federally protected species like the critically endangered North Atlantic right whale. Increased vessel traffic associated with offshore wind development, particularly during construction phases, could pose risks to the Gulf of Maine’s sea turtles and marine mammals. Minimizing collision risk during offshore wind farm construction and operation is vital to the continued conservation of vulnerable marine species. BOEM is conducting research to evaluate and mitigate the risks of fatal strikes to large whales and sea turtles on the Atlantic Outer Continental Shelf (OCS) during offshore wind energy development. Protective measures may include the use of real-time acoustic monitoring and aerial surveys to detect presence of whales, seasonal restrictions on offshore wind construction activities, and implementation of vessel speed limits. These types of measures and others will be used to protect North Atlantic rights whales during the construction of Vineyard Wind Project off the coast of Massachusetts.
Electromagnetic Fields Associated with Power Transmission
Like all power transmission cables, underwater power cables associated with offshore wind energy projects emit electromagnetic fields (EMF). Low intensity electromagnetic fields occur naturally throughout marine environments. Some marine species, including sharks, lobsters, and skates, rely on their ability to detect and use information from naturally occurring electrical and/or magnetic fields for navigation, migration, and predator/prey detection. Exposure to EMF emitted by underwater power transmission cables may inhibit the ability to detect naturally occurring EMF and may cause impairment to sensitive marine species. According to BOEM, the amount of electrical current being carried by the cable, the design of the cable, and the distance of marine organisms from the cable are all factors that determine the level of EMF exposure a marine organism may experience from transmission cables. Bottom dwelling fish and invertebrates, like skates and lobsters, are most at risk of EMF exposure.
Mitigation measures can help to reduce the levels of EMF exposure experienced by marine organisms. Transmission cables can be fitted with grounded metallic coverings that reduce the strength electrical fields emitted from the cable. To reduce the strength of magnetic field emissions, cables can be buried several feet beneath the seafloor. Increased burial depth reduces magnetic field at the seafloor. Recent research suggests that with proper mitigation measures, the overall impact of EMF emitted from offshore wind transmission cables on marine species health is likely minimal. However, more research may be needed to evaluate specific biological impacts of EMF exposure and how exposure may affect the viability of commercial and recreational fisheries. Although offshore wind turbines will be situated in Federal waters, associated transmission cables are likely to traverse State waters and could affect inshore fishing activities, such as lobstering.
Illustration of an underwater power cable associated with a floating turbine. Power cables used to transmit electricity to the shore would be buried beneath the seafloor or covered with concrete.
Illustration by Josh Bauer, NREL 49057
Entanglement Risks
Floating offshore wind turbines are anchored to the seafloor using a set of mooring cables that pass through the water column. Inter-array transmission cables also pass through the water column within an offshore wind farm, connecting each turbine electrically. BOEM has funded research to evaluate the risk that this infrastructure might pose to marine mammals traveling through the water column while foraging and migrating. Due to the size and spacing of cables used in floating turbine wind farms, it is unlikely that offshore wind cables would be an entanglement risk for marine mammals. However, lost fishing gear that becomes caught on underwater cables could significantly increase entanglement risks for marine mammals travelling through offshore wind farms. Entanglement with fishing gear is a leading cause of death for large whales, including the federally listed Northern Atlantic right whale. Research is being conducted on remote sensing technologies that can detect the presence of fishing gear that has become tangled with offshore wind infrastructure.
This video, produced by BOEM, simulates a hypothetical encounter between humpback whales and a floating offshore wind turbine farm. Click here to learn more about BOEM's research on this topic
Coastal and Shoreline Development
Successful offshore wind development requires support from onshore infrastructure, including turbine assembly areas, port facilities, a site for onshoring power, and related power grid infrastructure. New Hampshire’s coastal ecosystems already face threats from multiple stressors, including habitat loss, stormwater pollution, storm surges, and rising sea level, so minimizing environmental impacts from offshore wind development is critical to the continued conservation of the state’s coastline. Increased port development, manufacturing and assembly activities, landfall of transmission cables, and improvements to grid infrastructure may cause disturbance the State’s sensitive coastal areas.
Hampton beachgrass restoration, photo credit: Rebecca Zeiber, N.H. Sea Grant
The U.S. Environmental Protection Agency, National Oceanic and Atmospheric Administration, United States Army Corps of Engineers, and a number of state agencies, including the NH Department of Environmental Services and the NH Fish and Game Department, through the NH Site Evaluation Committee process, would be responsible for conducting environmental reviews of onshore development related to offshore wind projects. Environmental permits, like land development permits and wetland permits as well as Coastal Zone Management Act federal consistency review, would likely be required for offshore wind projects and associated onshore infrastructure. Learn more about how the NH coast is protected here.
How does BOEM consider environmental impacts during the development process?
BOEM requires extensive evaluation and review of impacts on the environment in its leasing process. BOEM is required by the National Environmental Policy Act (NEPA) to assess the environmental impacts of proposed offshore wind development projects and to consider reasonable mitigation measures. Potential impacts of offshore wind development on sensitive offshore habitats, coastal and marine species (such as marine mammals, birds, sea turtles, bats), fisheries, and archaeological/cultural sites, are some of many impacts that are analyzed during this review.
Offshore wind developers holding leases in the Outer Continental Shelf must also conduct several types of environmental surveys prior to approval of proposed projects. The results of these surveys are evaluated by BOEM before the agency authorizes proposed projects. Pre-construction environmental surveys that are required by BOEM include:
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a spatial site characterization survey
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an archaeological and historic property survey
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a geophysical, geotechnical and geohazard survey
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a fisheries survey
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an avian survey
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a benthic habitat survey
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a marine mammal and sea turtle survey
Offshore wind projects must also comply with other federal environmental regulations including the U.S. Endangered Species Act, Magnuson-Stevens Fishery Conservation and Management Act, and the Marine Mammal Protection Act. BOEM collaborates with federal agencies, like the National Marine Fisheries Service (NMFS) and the United States Fish and Wildlife Service (USFWS), that are responsible for the implementation of these laws and policies.