When the Interior Department in late August approved construction of a wind farm off the Rhode Island coast, it imposed an unusual restriction on the developer — do not use the most powerful turbines.
The order reflects a critical juncture facing the offshore wind industry, which could provide three times the amount of electricity that the entire U.S. now generates, according to the Department of Energy’s National Renewable Energy Laboratory.
As the Biden administration boosts offshore wind to help meet its climate targets, developers are trying to make wind power inexpensive by installing increasingly large and powerful turbines aimed at improving efficiency.
But as developers plan for turbines that stand 800 feet — higher than the Golden Gate Bridge towers — federal officials and experts are warning that the models will take years to produce and could increase wind power costs.
“When you build a machine of that size, there are a lot of problems that you have to work out, and those haven’t been worked out yet,” Walt Musial, a principal engineer at DOE’s energy lab, said in an interview.
A DOE report by Musial released just after the Rhode Island decision says that turbine manufacturing facilities need improvements costing billions of dollars before they can produce 800-foot models. The upgrades would delay offshore wind projects and increase construction costs, according to DOE’s Offshore Wind Market Report for 2023.
An August report by Wood Mackenzie, a global energy consulting firm, called the drive for larger wind turbines an “arms race” that could delay construction and set back wind goals worldwide.
“It’s a huge risk that we’re now seeing for projects,” said Finlay Clark, a Wood Mackenzie senior offshore wind analyst and one of the report’s authors.
For decades, manufacturers have produced larger, more powerful turbines every few years as developers sought to reduce construction and maintenance costs by using fewer towers per offshore wind farm.
The two U.S. offshore wind farms currently in operation — in Rhode Island and Virginia — have seven turbines combined. All of them generate up to 6 megawatts of power depending on wind strength. One MW can power 400 homes, according to the Biden administration.
At least six planned offshore wind projects, including Atlantic Shores in New Jersey and Empire Wind off Long Island, will use turbines that can generate 14 or 15 MW, according to Vestas and Siemens Gamesa, the European manufacturers building the turbines.
Only a handful of factories outside of China produce 14-MW turbines. Developers of the six wind projects expect the larger turbines to be commercially available in the next year or two.
Equinor, a Norwegian state-owned energy company developing Empire Wind, acknowledged to E&E News that the growing turbine size is “threatening profitability” and said it is working “to find ways of achieving our goals.”
“Growing pains will diminish over time,” Equinor said.
But developers are ignoring “the risk in going to those larger machines, or whether the supply chains and the vessels and the ports are going to be able to accommodate those machines,” Musial said.
“Larger turbines always look better on paper,” he added.
Offshore wind is key to renewable energy goals
The Biden administration wants to add 30,000 MW of offshore wind by 2030 that can power 10 million homes. Wind produces 10 percent of U.S. energy, almost all of which comes from onshore wind farms scattered from Texas to Iowa to California. Onshore turbines generate at most 3 MW.
Offshore wind farms could generate far more power because they can use larger turbines and wind is stronger and more consistent at sea.
Offshore wind farms are as reliable as gas-fired power plants and supplement power from solar and onshore wind farms, both of which depend heavily on weather conditions, according to the International Energy Agency.
The administration’s wind goals focus on installing about2,100 more offshore turbines, according to DOE’s energy lab.
The turbines would have to generate on average about 14 MW to meet the 30,000-MW goal. The Interior Department limited the new Rhode Island Revolution Wind project to turbines that generate up to 12 MW.
The biggest problem with 14-MW or larger turbines is their unproven reliability, experts say.
Testing sites are not designed to handle the large blades in a 14-MW turbine. And because 14-MW turbines are new products — not upgrades to older turbines — they require extensive testing, Musial of the energy lab said.
A Boston testing site that opened in 2011 can measure the durability of blades up to 300 feet long and is the only blade testing site in North America. But the turbines for the Vineyard Wind project under construction off Massachusetts’ coast will use General Electric’s 13-MW models with 350-foot blades.
GE was forced to trim its blades to 300 feet to fit the test facility and get certification, according to the Massachusetts Clean Energy Center, a state-owned research group that runs the facility.
But trimming will not work for new turbines with blades reaching nearly 400 feet, which would require an expansion of the testing site, the center said.
Even after turbines are certified, the new designs could run into unforeseen failures in the ocean, where they have no track record of operating, Musial said.
The projects will also face problems with transportation and construction.
The offshore platforms on which wind turbines are assembled and driven into the ocean floor are too small to handle the larger components. So are the barges and tugboats that haul components to the platforms, said Sam Salustro, a vice president at the Business Network for Offshore Wind.
The U.S. needs at least 100 ships to meet the administration’s 2030 goal, but only 36 are being built, Salustro said.
More than 20 new platforms are needed to meet international wind goals, but installers have committed to less than half that number, the Wood Mackenzie report says.
Insurers, concerned about reliability, could also slow construction by denying coverage to the larger offshore wind farms for project delays or component failures, according to GCube, an insurance firm specializing in renewable energy projects.
‘A monster we created’
The U.S. is unlikely to reach President Joe Biden’s offshore wind goal, according to BloombergNEF, which projects 23 gigawatts of new capacity will come online by 2030.
The Biden administration is “using every legally available tool” to advance offshore wind projects, a White House spokesperson said in an email. “Since President Biden signed the Inflation Reduction Act [in August 2022], investments in the U.S. offshore wind industry have increased by $7.7 billion — creating thousands of good-paying union jobs across the country in manufacturing, shipbuilding, and construction.”
Despite high risk, developers and manufacturers continue to pursue larger turbines. GE and two Chinese manufacturers are developing 1,000-foot, 18-MW turbines.
Many manufacturers fear that if they stop building larger turbines, customers will buy them from other companies, said John Eggers, Vestas’ U.S. chief technology officer. Vestas says it won’t develop turbines bigger than its 15-MW prototype because transporting larger machines is difficult.
Eggers said manufacturers have fueled the growth in turbine size by producing new, larger models every few years.
“It’s a monster we created. It’s a monster we have to stop,” Eggers said.