Climate change threatens many marine species, but some climate solutions pose risks, too. Researchers say offshore wind needs continued study and better regulations.

Gull flying with turbines in the background

A key part of the United States’ clean energy transition has started to take shape, but you may need to squint to see it. About 2,000 wind turbines could be built far offshore, in federal waters off the Atlantic Coast, in the next 10 years. And more are expected.

East Coast states from Maine to North Carolina are working to procure nearly 30 gigawatts of offshore wind by 2035 — a huge leap from the five turbines currently generating 30 megawatts in Rhode Island waters. If a regulatory backlog of projects awaiting approval from the Interior Department’s Bureau of Ocean Energy Management is finally unstuck — as experts hope will happen this year — the buildout of offshore wind will arrive during a crucial decade for reducing greenhouse gas emissions.

Spinning turbine blades on the watery horizon may be a welcome sight in the fight against climate change, but they still come with potential threats to marine wildlife. Many environmental groups believe the challenges aren’t insurmountable if scientific study can help inform regulatory action and if we can learn — and adapt our practices — as we go.

“We believe that offshore wind can absolutely be developed in an environmentally responsible manner,” says Francine Kershaw, a staff scientist at the Natural Resources Defense Council. “But that has to be incorporated throughout the whole process — from site assessment through development, construction and operations.”

Threats to Birds

One of the gravest threats facing birds is climate change, according to Audubon, which found that rising temperatures threaten nearly two-thirds of North America’s bird species. That’s why the impending development of offshore wind is a good thing, says Shilo Felton, a field manager in the organization’s Clean Energy Initiative, but it also comes with dangers to birds that need to be better studied and mitigated.

The most obvious risk comes from birds colliding with spinning turbine blades. But offshore wind developments can also displace birds from foraging or roost sites, as well as migratory pathways.

Along the Atlantic Coast four imperiled species are of top concern to conservationists: the endangered piping plover, red knot, roseate tern and black-capped petrel, which is being considered for listing under the Endangered Species Act.

“Those four species are of utmost importance to make sure that we understand the impacts,” says Felton. “But beyond that there are many species that are protected under the Migratory Bird Treaty Act and the Fish and Wildlife Conservation Act that could potentially see more impacts from offshore wind.”

Northern gannets, for example, are at risk not just for collision but habitat displacement.

northern gannet flying
A northern gannet flying along Cape May, N.J. Photo: Ann Marie Morrison, (CC BY-NC-ND 2.0)

“There’s some evidence that they just won’t use areas where turbines are, but that also excludes them from key foraging areas,” says Felton. Researchers are still studying what this may mean for the birds. But a study published in December 2020 conducted at Bass Rock, Scotland —  home to the world’s largest northern gannet colony — found that wind developments could reduce their growth rate, though not enough to cause a population decline.

Other birds, such as great cormorants and European shags, are attracted to wind developments and use the infrastructure to rest while opening up new foraging areas farther from shore.

“There’s plenty of potential for a bird to use a wind farm and still to avoid the turbines themselves,” says Felton.

Birds like pelicans, however, are less versatile in their movements and are at particular risk of collision because of their flight pattern, she says.

But how disruptive or dangerous offshore turbines will be along the East Coast isn’t yet known.

Federal and state agencies, along with nongovernmental organizations, says Felton, have done good research to try to better understand those potential impacts. “But these are all theoretical, because we don’t have a lot of offshore wind yet in the United States.”

Threats to Ocean Life

Birds aren’t the only wildlife of concern. More development in ocean waters could affect a litany of marine species, some of which are already facing other pressures from overfishing, pollution, habitat destruction and climate change.

Scientists have found that marine mammals like whales and dolphins could be disturbed by the jarring sounds of construction, especially if pile driving is used to hammer the steel turbine platform into the seafloor.

The noises, though short-lived, could impede communication between animals, divert them from migration routes or cause them to seek less suitable areas for feeding or breeding. Research from Europe found that harbor porpoises, seals and dolphins may avoid development areas during construction. In most, but not all cases, the animals were believed to have returned to the area following construction.

The biggest concern for conservation groups in the United States is the critically endangered North American right whale. There are fewer than 400 remaining, and the species’ habitat overlaps with a number of planned wind development areas along the East Coast.

“Offshore wind is in no way the cause of the challenges the whales face, but it’s going to be another pressure point,” says John Rogers, senior energy analyst for the Union of Concerned Scientists.

Researchers aren’t sure how right whales will respond to the noise from pile driving.

“But we are concerned, based on what we know about how whales react to other noise sources, that they may avoid [wind development] areas,” says Kershaw.

And if that displacement causes them to miss out on important food resources, it could be dangerous for a species already on the brink.

There are a few other potential threats, too.

Ships associated with the development — more plentiful during construction — also pose a danger. In the past few years cargo ships, fishing boats and other vessels have caused half of all deaths of North Atlantic right whales.

whale breaching
A juvenile right whale breaches against the backdrop of a ship near the St. Johns River entrance. Photo: Florida Fish and Wildlife Conservation Commission, NOAA Research Permit #775-1600-10

And after construction, the noise from the spinning turbines will be present in the water at low decibels. “We don’t quite know how the great whales will react to those sounds,” says Jeremy Firestone, the director of the Center for Research in Wind at the University of Delaware.

Other marine mammals may also perceive the noise, but at low decibels it’s unlikely to be an impediment, research has found.

And it’s possible that wind development could help some ocean life. Turbine foundations can attract fish and invertebrates for whom hard substrates create habitat complexity — known as the “reef effect,” according to researchers from the University of Rhode Island’s Discovery of Sound in the Sea program. Exclusion of commercial fishing nearby may also help shelter fish and protect marine mammals from entanglements in fishing gear.

Ensuring Safe Development

Despite the potential dangers, researchers have gathered a few best practices to help diminish and possibly eliminate some risks.

When it comes to ship strikes, the easiest thing is to slow boats down, mandating a speed of 10 knots in wind development areas, and using visual and acoustic monitoring for whales.

Adjusting operations to reduce boat trips between the shore and the wind development will also help. A new series of service operating vessels can allow maintenance staff to spent multiple days onsite, says Kershaw, cutting down on boat traffic.

For construction noise concerns, developers can avoid pile driving during times of the year when whales are present. And, depending on the marine environment, developers could use “quiet foundations” that don’t require pile driving. These include gravity-based or suction caisson platforms.

Floating turbines are also used in deep water, where they’re effectively anchored in place — although that poses its own potential danger. “We have concerns that marine debris could potentially become entangled around the mooring cables of the floating arrays and pose a secondarily entanglement risk to some species,” says Felton, who thinks more research should be conducted before those become operational in U.S. waters — a process that’s already underway in Maine, where a demonstration project is being built.

If loud noises are unavoidable during construction, noise-reducing technologies such as bubble curtains can help dampen the sound. And scheduling adjacent projects to conduct similar work at the same time could limit the duration of disturbances.

ship working at sea
The foundation installation of the off shore wind farm Sandbank using a bubble curtain. Photo: Vattenfall/Ulrich Wirrwa, (CC BY-NC-ND 2.0)

Once turbines become operational, reducing the amount of light on wind platforms or using flashing lights could help deter some seabirds, NRDC researchers reported. And scientists are exploring using ultrasonic noises and ultraviolet lighting to keep bats away. “Feathering,” or shutting down the turbine blades during key migration times, could also help prevent fatalities.

“We need to make sure that offshore wind is the best steward it can be of the marine ecosystem, because we want and expect it to be a significant part of the clean energy picture in some parts of the country,” says Rogers. “We also have to recognize that we’re going to learn by doing, and that some of these things we’re going to figure out best once we have more turbines in the water.”

That’s why environmental groups say it’s important to establish baseline information on species before projects begin, and then require developers to conduct monitoring during construction and for years after projects are operational.

Employing an “adaptive management framework” will ensure that developers can adjust their management practices as they go when new information becomes available, and that those best practices are incorporated into the requirements for future projects.

Putting Research Into Action

Advancing these conversations at the federal level during the Trump administration, though, has been slow going.

“We didn’t really have any productive discussions with the administration in the last four years,” says Kershaw.

And when it comes to birds, Felton says the Bureau of Ocean Energy Management’s recently completed “draft cumulative environmental impact statement” covering offshore wind developments had a lot of good environmental research, but little focus on birds.

“Part of that comes from the current administration’s interpretation of the Migratory Bird Treaty Act,” she says.

President Trump has been hostile to both wind energy and birds, and finished gutting the Migratory Bird Treaty Act in his administration’s the final days, removing penalties for companies whose operations kill migratory birds.

There’s hope that the Biden administration will take a different approach. But where the federal government has been lacking lately, Kershaw says, they’ve seen states step up.

New York, for example, has established an Environmental Technical Working Group composed of stakeholders to advise on environmentally responsible development of offshore wind.

The group is led by the New York State Energy Research and Development Authority, but it isn’t limited to the Empire State. It’s regional in focus and includes representatives from wind developers with leases between Massachusetts and North Carolina; state agencies from Massachusetts to Virginia; federal agencies; and science-based environmental NGOs.

New York’s latest solicitation for clean energy projects includes up to 2,500 megawatts of offshore wind and requires developers to contribute at least $10,000 per megawatt for regional monitoring of fisheries and other wildlife.

Environmental groups have also worked directly with developers, including an agreement with Vineyard Wind — an 800-megawatt project off the Massachusetts coast that could be the first utility-scale wind development in federal waters — to help protect North Atlantic right whales.

The agreement includes no pile driving from Jan. 1 to April 30, ceasing activities at other times when whales are visually or acoustically identified in the area, speed restrictions on vessels, and the use of noise reduction technology, such as a bubble curtain during pile driving.

“The developers signed the agreement with us, and then they incorporated, most, if not all of those measures into the federal permitting documents,” says Kershaw. “The developers really did a lot of bottom up work to make sure that they were being very protective of right whales.”

Environmental groups are in talks with other developers on agreements too, but Felton wants to see best practices being mandated at the federal level.

“It’s the sort of a role that should be being played by the federal government, and without that it makes the permitting and regulation process less stable and less transparent,” she says.” And that in turn slows down the build out of projects, which is also bad for birds because it doesn’t help us address and mitigate for climate change.”

Kershaw agrees there’s a lot more work to be done, especially at the federal level, but thinks we’re moving in the right direction.

“I think the work that’s been done so far in the United States has really laid the groundwork for advancing this in the right way and in a way that’s protective of species and the environment,” she says. “At the same time, it’s important that offshore wind does advance quickly. We really need it to help us combat the worst effects of climate change.”

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Tara Lohan

worked as The Revelator's deputy editor from 2018-2024. She is the editor of two books on the global water crisis and is working on a book about dam removal.