It seems like an insurmountable engineering feat: Tow concrete hulls weighing 12,000 tons far offshore, erect towers atop them that rise hundreds of feet above the ocean with rotor blades the span of a football field, and somehow get them to produce significant amounts of wind energy despite the violent seas and notorious weather of the North Atlantic Ocean.
All that without embedding the colossal structures into the seafloor, because unlike traditional offshore wind turbines, these will float.
And that’s exactly what Habib Dagher intends to pull off in the Gulf of Maine, with the first of these monumental structures planned for a location a few miles off the coast of Monhegan Island in 2025.
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Dagher is the executive director of the Advanced Structures and Composites Center at the University of Maine in Orono, and his is the first in the United States of the next generation of wind turbines that are the new great hope of the clean energy world. Federal officials estimate that two-thirds of the nation’s potential wind power are in waters too deep for traditional wind turbines, with some of the best locations off the coast of New England, particularly the Gulf of Maine.
“This is a major opportunity,” said Dagher, who has been researching and designing floating turbine technology for more than a decade. “There’s enough offshore wind to power the country four times over, all within 50 miles of shore.”
Engineers such as Dagher envision vast floating wind farms in the Gulf of Maine, where federal officials estimate that reliable gusts well offshore have the capacity to generate more than five times the amount of electricity used on an average day in New England. But their vision has sparked criticism from fishermen, who have raised concerns about the impact of floating turbines on marine life and worry about their ability to fish in industrialized waters.
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Dagher’s team has received millions of dollars in research and development funding from the federal government, which has been promoting floating wind as a way to solve the thorny problems of erecting turbines too close to shore, where they tend to stoke opposition, and to take advantage of all the potential wind power farther out.
His design relies on steel-reinforced concrete hulls, each with three massive, partially submerged columns, that are specially designed to limit the pitch of their turbines by only a few degrees — even in 70-foot waves and gusts of more than 100 miles per hour.
His team members’ first prototype, tested in 2013, proved their concept, as have similar projects built more recently off the coast of Scotland and elsewhere in Europe, they said. Scotland this year raised nearly $1 billion from leases of coastal waters for the construction of 15 gigawatts of floating wind power, enough for some 5 million homes.
The floating turbine the team is designing for the location off Monhegan Island would have an 11-megawatt capacity. In addition to the large columns, the turbines would have a range of technologies to keep them stable in the water: heavy mooring lines that weigh about 15 pounds per foot and would be attached to multiple anchors weighing as much as 40 tons; software that automatically moves the rotor blades for optimal energy output; and the equivalent of seismic dampers used in buildings to reduce their movement during an earthquake.
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“On a regular day, you would have a hard time seeing it was moving,” Dagher said. “It would look fixed.”
If they can overcome regulatory and political hurdles, and the turbine proves to be sufficiently robust to handle the rough seas, Dagher’s team plans to build a floating farm of a dozen turbines with a capacity for nearly 150 megawatts about 20 miles to the south.
Biden administration officials announced a plan in September to create 15 gigawatts of electricity with floating turbines by 2035. That’s on top of a previous administration goal to build 30 gigawatts of offshore wind using traditional turbines by 2030.
Their plan, part of Biden’s pledge to cut the nation’s carbon emissions by half by the end of the decade, focuses on installing floating turbines in the Gulf of Maine and off the West Coast, where the waters are too deep for traditional turbines.
Last month, Energy Secretary Jennifer Granholm disclosed plans for $50 million in research on the technology and called the administration’s ambitions a “big, hairy audacious goal,” adding that Biden is “all in on making floating offshore wind a real part of our energy mix,” the Associated Press reported.
She said the money, as well as a recently launched competition for new technology, aims to lower the costs of floating wind by 70 percent by 2035.
“We think the private sector is going to quickly see the real opportunity here not only to triple the country’s accessible offshore wind resources but to make the US a global leader in manufacturing and deploying offshore wind,” she said.
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But the prospect of large wind farms has sparked an outcry from some local fishermen and environmental groups.
Fishermen worry that webs of mooring lines — each the thickness of a telephone pole — crisscrossing the seafloor and attached to massive anchors could make it difficult for them to set their traps or tow their nets.
“We have great reservations of offshore wind development,” said Erik Anderson, president of the New Hampshire Commercial Fishermen’s Association. “There are so many questions — environmental, marine life, economic, and otherwise — that have not been sufficiently answered or investigated to support the enormous commitment to strategy.”
In response to a recent request for comments from the US Bureau of Ocean Energy Management, which is considering potential locations for floating wind farms in the Gulf of Maine, Anderson urged the agency to ban such development.
The noise and electromagnetic fields created by the turbines, he warned, could have “grave consequences” in the Gulf of Maine, which he described as an “environmentally sensitive body of water with enormous and untold productivity in all aspects of marine life.”
He and others in the fishing industry also worry about the challenges of navigating around the turbines and the mooring lines.
“New industrial ocean development should be only approached in full consideration of domestic food security and the cultural and economic needs of our coastal communities,” said Annie Hawkins, executive director of the Responsible Offshore Development Alliance, a coalition of fishing groups and companies.
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She fears federal officials will “lease first and ask questions later.”
Proponents of floating wind in the Gulf of Maine said deeper waters would mean significantly less conflict with fishermen, most of whom fish closer to shore. Farther out to sea, they’re also less likely to spark opposition from those concerned about their views.
Dagher said his team has been moving slowly, in concert with state and federal officials, to ensure they minimize such conflicts.
“We’ve heard from the industry, and that’s why we’re slowing down,” he said.
His team had hoped to have installed 5 gigawatts worth of floating wind power — enough to power all of Maine — by the end of the decade. Instead, they don’t plan to build any large wind farms in the Gulf of Maine until then.
“The concerns of the fishing industry are important to us,” Dagher said. “We want to do this right and take a deliberate approach.”
Some environmental groups have teamed up with fishing groups, echoing calls from the New England Fishery Management Council for federal officials to conduct a comprehensive environmental review before installing wind farms in the Gulf of Maine.
Federal officials, however, have declined to do that.
Environmental advocates worry about the impact of sub-surface noise from the turbines and marine debris, such as old fishing rope, becoming ensnared on the mooring lines, potentially entangling endangered marine mammals such as North Atlantic right whales. The lines themselves are too thick and taut to entangle whales.
Erica Fuller, a senior attorney at the Conservation Law Foundation in Boston, said the government’s decision “epitomizes short-term thinking that will only cause problems in the long run.”
“It is critical to advance offshore wind to respond to the climate crisis and clean up our electric grid, but it must be done in a science-based, inclusive, and transparent way,” she said.
Officials at the Bureau of Ocean Energy Management said that they are still in the early phases of planning where to build wind farms in the Gulf of Maine and that they have other ways of assessing environmental risks. They added that the federal government has already invested millions of dollars in studying the region’s marine ecosystems and that they have refined their process for identifying locations for offshore wind.
“We are confident that [our] approach, which employs the best available science and information, will identify the least conflicted areas that still deliver the renewable energy capacity necessary to meet administration and state renewable energy goals,” said Tracey Moriarty, a spokeswoman for the bureau.
At a recent conference on floating wind in Portland, Jocelyn Brown-Saracino, who oversees offshore wind energy policy at the US Department of Energy, said it was time to start moving ahead with efforts to harness the vast wind power available in the Gulf of Maine.
She said floating wind was “poised to be a central pillar of our clean energy future.”
“Its promise is immense,” she said, “but we have a lot of work to do.”
David Abel can be reached at david.abel@globe.com. Follow him @davabel.