Two of the country’s first large-scale offshore wind farms are now fully operational, the developers announced this week, promising to power a combined 750,000 homes in Connecticut, Rhode Island, and Massachusetts.
Vineyard Wind became fully operational on Oct. 29, spokesperson Craig Gilvarg confirmed in an email to The Light Friday. On Thursday, another project, Revolution Wind, announced it had also come fully online after three years of construction.
Both projects finished installing their wind turbines earlier this year, Vineyard Wind in March and Revolution Wind in September. The new milestone means that all of the projects’ turbines are fully functional and capable of delivering power to the grid.
Both projects also faced considerable stops and starts from an adversarial federal government, including an attempt last month to pull permitting for Revolution Wind after the project had already been completed.
Green energy advocates celebrated the milestone, which they said would eliminate 1.6 million metric tons of carbon pollution annually — the equivalent of taking 325,000 cars off the road.
“A fully operational Vineyard Wind means New England families have another clean, affordable, local source of energy being delivered to their homes through the coming winter season,” Conservation Law Foundation Staff Attorney Anxhela Mile said in a statement Friday. “Federal and state leaders should be preparing to build out more of these projects to help lower energy costs and keep our air clean.” Vineyard Wind, a 62-turbine wind farm roughly 15 miles south of Martha’s Vineyard, delivers power to Massachusetts. Revolution Wind, a 65-turbine wind farm south of Block Island, delivers power to Rhode Island and Connecticut. The projects are key to the states’ clean-energy goals, given New England’s lack of open space for large-scale solar or onshore wind projects.
Although both projects just became fully operational, both have been delivering power to the grid for much longer, albeit at a reduced capacity.
Vineyard Wind produced 336,382 megawatt-hours between July and September of this year, according to recently released Federal Energy Regulatory Commission data. The Light’s analysis finds that’s enough to power approximately 193,300 Massachusetts homes. The project’s developer says it will power 400,000 homes once fully operational.
Revolution Wind is on a similar track. The project delivered 314,321 megawatt-hours between July and September of this year, roughly 22,000 megawatt-hours less than Vineyard Wind. The developer says it will power 350,000 homes once fully operational. Averages don’t tell the full story, however. Roger Williams University engineering professor Gordon Stewart cautioned that wind energy is cyclical and generally less predictable than other forms of energy. For example, power generation is generally expected to peak in the winter months when winds are stronger, and slump again in the summer. This pattern held true for Vineyard Wind, which produced approximately 410,400 megawatt-hours from October through December 2025 compared to 323,600 from April through June 2026.
But just because there is wind doesn’t mean that all the turbines are capturing it — and private companies tend to be secretive about engineering setbacks. Vineyard Wind, for example, took 7½ months to go fully online after completing construction, compared to 1½ months for Revolution Wind.
Vineyard Wind’s lawsuit against GE Vernova earlier this year seemed to blame the turbine supplier for the project’s struggles to reach full capacity. In May, Vineyard Wind said in court filings and hearings that the project was producing “less than half of its expected capacity,” and that 36 of the 62 turbines were not spinning. The lawsuit sought to prevent GE Vernova from exiting its contract to service and maintain the turbines before final commissioning work was complete. The parties settled in September after GE Vernova withdrew its notice of contract termination.
For this reason, next quarter’s data — as New England enters its windiest season — will be all the more revealing, Stewart said.
“It’ll be interesting to see if (the projects) are fully operational,” Stewart said. “And I think we’ll be able to see that.”
Even when everything goes right, wind farms aren’t expected to operate at 100% efficiency — no energy project is. As Stewart calculated for a previous Light analysis of Vineyard Wind’s output data, the developer’s estimate that the project will power 400,000 homes roughly corresponds to a 50% capacity factor; in other words, the wind farm is only going to be 50% efficient on average.
Most offshore wind farms have a capacity factor between 40% and 50%. Onshore wind farms tend to have a lower capacity factor, because the turbines are smaller and wind is generally less powerful on land, Stewart said. Nuclear power plants, meanwhile, have a capacity factor of 90% or more, and coal plants average around 42%, according to federal data.
Vineyard Wind’s Gilvarg did not answer The Light’s question about how many turbines were operational as of Sept. 1. Federal data indicates that Vineyard Wind operated at closer to 25% capacity this past year as it worked to get up and running.
“My gut feeling looking at these numbers is that roughly half of their turbines were operating at any one time,” Stewart said.
A third completed wind project, South Fork Wind, 35 miles east of Long Island, offers a glimpse into Vineyard Wind and Revolution Wind’s potential future. The 12-turbine wind farm, completed in 2024, generated roughly one-third of the power that Vineyard Wind and Revolution Wind produced despite being one-fifth the size. That means South Fork Wind reached a capacity factor nearly double that of the two in-progress projects.
Given the capriciousness of both Mother Nature and manmade technology, it will take months or even years to determine how efficient these wind farms are, Stewart said.
What the companies are still working out, he added, is how they will change tack in ever-changing winds.
For example, although each turbine’s position is fixed, companies can program some turbines’ blades to face different directions than others’. They can also power down front-facing turbines that could block wind from reaching the rest of the farm. These decisions will have a negligible effect on overall wind patterns, Stewart added, but could help the farm deliver more power to consumers.
“We’re going to learn a lot from these first two large-scale farms, and next year, it’ll be really interesting to see what kind of power they make,” Stewart said.
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This story was originally published by The New Bedford Light and distributed through a partnership with The Associated Press.
