New utility contracts would double state’s offshore wind capacity, and bring new jobs to Somerset and Salem waterfronts

One contract, with Commonwealth Wind, has prompted an Italian manufacturer to build an undersea-cable factory at the site of the former Brayton Point power plant.

Energy Secretary Kathleen Theoharides spoke in May at the state's wind blade testing center in Charlestown about the announcement that the federal government has approved Vineyard Wind's permit. She returned to the site on Friday to announce the latest progress with the offshore wind industry.David L. Ryan/Globe Staff

Two waterfront sites in Salem and Somerset that were once home to giant coal-burning plants will soon play crucial roles in the transition to wind power under new contracts announced by state officials on Friday.

Commonwealth Wind, an offshore wind proposal from Avangrid, won utility contracts to finance towering turbines that will together generate roughly 1,200 megawatts of electricity, enough for 600,000-plus homes. Commonwealth Wind will go up in federal waters more than 20 miles south of Martha’s Vineyard, not far from a sister project called Vineyard Wind. Avangrid plans to use the old coal-plant site on Salem Harbor as a staging area for wind turbine assemblies for Commonwealth Wind.

The contract win also prompted a commitment from Italian manufacturer Prysmian Group to build a cable factory at the former Brayton Point power plant site in Somerset, creating as many as 200 jobs.

“This is the first time we’ll actually see offshore wind manufacturing jobs here,” said Bill White, who leads Avangrid’s offshore wind efforts.

Brayton Point, it turns out, will also play a key role in rival Mayflower Wind’s project, which will be built in waters southeast of Avangrid’s. Mayflower Wind — owned by Shell, EDP Renewables, and Engie — just won contracts to generate 400 megawatts, expanding that proposed wind farm’s capacity to 1,200 megawatts. Mayflower Wind, for this stage, will use Brayton Point to connect with the region’s electric grid, via a 90-plus-mile undersea cable. (That’s a change from now-delayed plans to connect through Cape Cod.)

“It’s kind of poetic, isn’t it?” Mayflower Wind chief executive Michael Brown said of the former coal plant site’s conversion for wind power use.

And from White’s perspective, he said the transition “is realizing the dream that we’ve talked about for so long.”

Mayflower Wind, Commonwealth Wind, and the 800-megawatt Vineyard Wind collectively represent 3,200 megawatts. That’s enough power for more than 1.6 million homes, or roughly one-quarter of the state’s electricity demand. Vineyard Wind is furthest along of any utility-scale offshore wind farm in the country, with a groundbreaking ceremony held last month and a completion date of 2023. The other two will take five to seven years to permit and build.

Susannah Hatch, clean energy coalition director with the Environmental League of Massachusetts, said she is relieved the state’s main electric utilities, namely Eversource and National Grid, and the Baker administration awarded contracts for the maximum amount available in this round of bidding — 1,600 megawatts.

“It meant they ended up choosing two developers, so everybody wins,” Hatch said.

The electricity pricing has not yet been disclosed for the latest round, though both winning bidders needed to beat an aggressive price cap, with likely help from a generous federal tax credit program.

These contracts are expected to bring billions of dollars in infrastructure investments, as well as thousands of construction jobs, and hundreds of permanent ones. Massachusetts, a first mover in offshore wind, had been losing ground in the race for industry jobs and investments to New York and New Jersey. (Coincidentally, the state of Maryland announced about 1,600 megawatts of wind energy credits on Friday as well.) Avangrid will maintain a base of operations in New Bedford, home to a state-funded turbine assembly terminal, while Mayflower Wind operations will be supported by crews out of Fall River.

The latest round of contracts, announced at a wind-blade testing center in Charlestown, represents a strong step forward for the state’s clean-energy initiatives, particularly after a power line to import hydroelectricity from Canada was rejected by Maine voters in a referendum last month.

“These projects are allowing us to hit our climate targets while investing in communities that often bore the brunt of our old energy system,” said Katie Theoharides, Governor Charlie Baker’s energy secretary. “When you think about climate solutions, these are exactly the kind of climate solutions you want to build.”