Ten developers are interested in building massive wind farms off the coast of Massachusetts that together could generate nearly 10 times the amount of energy as the controversial and long-stalled Cape Wind project.
The wind farms would be built in an expanse of federal waters larger than Rhode Island, about 14 miles south of Martha’s Vineyard and identified by the US Bureau of Ocean Energy Management as an ideal place for such development. After more than two years of talks with local and state officials, environmentalists, fishermen, and tribal leaders, the bureau last week refined the boundaries of the so-called wind energy area, whittling it down to 1,160 square miles from an initially proposed 3,000.
State officials provided a list of the 10 companies that have expressed interest in construction of a wind farm at that location.
The bureau said it would begin an environmental assessment of the area, which officials have estimated could produce as much as 4,000 megawatts of energy - enough to power an estimated 1.7 million homes. Construction of turbines likely would not begin for several years.
“It’s a very exciting opportunity for Massachusetts,’’ said Richard K. Sullivan Jr., the state’s energy and environmental affairs secretary. “It also puts Massachusetts in a very strong position to be the national leader in offshore wind.’’
The Bureau of Ocean Energy Management has been working to identify and assess other wind energy areas along the nation’s coast, and last year named federal waters off New Jersey, Delaware, Maryland, and Virginia as potential sites.
Governor Deval Patrick has made wind-generated energy a priority, championing the construction of Cape Wind, and setting a goal to have 2,000 megawatts worth of wind-power capacity by 2020. During the past decade, the state’s installed wind capacity has increased from less than a megawatt to nearly 60 megawatts, enough to power about 15,800 homes.
Tommy P. Beaudreau, director of the Bureau of Ocean Energy Management, said one of the main goals of designating the wind energy areas is to streamline the approval process for offshore wind projects.
Beaudreau’s agency was particularly deliberate in determining the wind energy area off Massachusetts in an effort to minimize conflicts like those experienced by Cape Wind, which faced a decade of opposition and legal fights before winning federal and state approval in 2010. The project still faces appeals.
“It’s really about trying to design or make available areas up front that have buy-in from the states and communities,’’ Beaudreau said. “There are a lot of takeaways from Cape Wind.’’
The wind energy areas are already drawing attention from wind farm companies, including Cape Wind developer Energy Management Inc., which say that federally-approved locations are likely to cut down on opposition to projects.
“For Massachusetts, this is the logical next step for offshore wind,’’ said Mark Rodgers, a spokesman for Cape Wind.
“The federal government is working with the state to try and ensure that by investing a lot of their energy on the front end, it will be easier for a company to take a project through the permitting and approval process,’’ he said.
Developers say wind energy areas will also be the proving ground for the next generation of wind turbines, each capable of generating 5- to 7-megawatts worth of power and being located far enough offshore so they would not be visible to many people. The prospect of turbine towers visible to Cape Cod landowners sparked much of the opposition to Cape Wind.
Currently, the industry’s standard offshore turbines generate about 3.6 megawatts of energy. Each megawatt produced by land-based wind turbines can power about 260 homes, but the strength of offshore winds is expected to make ocean wind farms more productive.
“It’s really the advent of these much larger turbines that makes these far out wind farms possible,’’ said Bill Moore, chief executive of Deepwater Wind LLC, a Rhode Island company already working to build a demonstration project off Block Island,using five 6-megawatt turbines.
Moore said his company responded to federal officials’ call for interest in Massachusetts’ wind energy area projects. So have nine other companies, including Iberdrola Renewables LLC, the US division of Spain’s largest energy company.
Rodgers, the Cape Wind spokesman, said his company will need to weigh the challenges of building in deeper federal waters against the potential payoff of a project that can generate large amounts of energy.
“It’s a much higher-wave environment, the distances for the transmission lines are significantly longer, ’’ he said.
Sue Reid of the nonprofit Conservation Law Foundation said federal and state officials have worked to identify potential problems, such as how construction will affect endangered North American right whales, fishing areas, bird populations, and boat traffic.
“We don’t want to find out six years into it that all of a sudden there’s a significant conflict with a transportation route or a right whale feeding area,’’ Reid said.
Audra Parker, president of the Alliance to Protect Nantucket Sound, a Cape Wind opponent, said such care should have been taken when deciding where to locate Cape Wind.
“There’s no site that doesn’t have issues, but it’s a matter of balancing the public interests with the technical criteria, the developer’s interests,’’ she said. “We have for years promoted the concept of marine special planning, both to protect certain sites and to all other sites for development.’’