enlarge Courtesy Principle Power Inc.

A deep-water wind farm like the one illustrated here might be built off the coast if Maine attracts a successful demonstration project.

enlarge Courtesy Blue H USA

A prototype platform that supports a wind turbine floats in the harbor of Brindisi, Italy. Blue H USA tested the platform in the Adriatic Sea and is now building the first unit for a planned floating wind farm to supply the power needs of 75,000 Italian homes.

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FOR INFORMATION about Maine's Ocean Energy Task Force, go online to www.maine.gov

International energy companies are looking at Maine to test new designs for massive wind turbines and support structures that would float in deep water, out of sight of the coast and in line with the strongest breezes.

Two of the businesses have been attending monthly meetings of Maine's Ocean Energy Task Force, which must identify up to five offshore demonstration sites before year's end.

The task force is considering a large amount of information, everything from water depths and wind speed to whale and bird migration routes. The goal is to locate areas that have robust wind but where turbines wouldn't bother fishermen, boaters, coastal residents and wildlife.

Successful test sites could make Maine a global contender for billions of dollars in energy investment over the next decade or so. They also would be a proving ground for the vision that offshore wind can someday heat Maine homes and power automobiles, freeing the state from dependence on petroleum.

Wind farms in Europe's shallow coastal waters have become common and are expanding. The United States is way behind in rolling out this technology, but shallow-water wind farms are pending along the East Coast in Massachusetts, Rhode Island, New Jersey and Delaware.

Meanwhile, engineers have grander visions. They have begun testing platforms that weigh hundreds of tons, float in more than 100 feet of water and support towers that stand nearly the length of a football field.

On a commercial scale, a floating, deep-water wind farm could have more than 100 turbines and generate the electricity equivalent of a large gas or nuclear power plant.

Prototypes have been placed off Norway and Italy, and are planned for Portugal and the United Kingdom. In the United States, demonstrations are proposed in Massachusetts and Oregon.

Maine has so far been left on the sidelines, although winds in the Gulf of Maine average more than 35 miles an hour in winter, when energy demand in New England is high. But meetings this year of the Maine task force and its broad collection of experts and stakeholders have drawn the attention of offshore wind companies.

"This is very encouraging for a company like Blue H," said Ray Dackerman, general manager of Blue H USA, subsidiary of a Dutch company. "It's really important to launch this industry in the United States, and we can do that in Maine and Massachusetts, once we have sites."

Blue H completed tests last year with a floating prototype in 370 feet of water in the Adriatic Sea, 13 miles off Italy. Now it's building the first unit for a planned 90-megawatt floating wind farm to supply the power needs of 75,000 Italian homes.

In Massachusetts, Blue H has federal applications out for a demonstration project 23 miles from Martha's Vineyard. It hopes to moor the platform off the coast by 2011. The long-term goal is to have 120 turbines floating in 167 feet of water, generating 420 megawatts.

As was the case in Italy, the unit would be built onshore and towed to the test site. Blue H will seek bids from companies in New England that can fabricate the patented structure.

MAINE COMPANIES MAY BENEFIT

That could mean new work for Maine contractors with marine construction experience, such as Bath Iron Works and Cianbro Corp. Both are involved with the task force and want to expand into offshore wind energy.

"The Maine companies will be in play," Dackerman said.

Bath Iron Works and Cianbro are "powerful assets" for wind developers that need to assemble units onshore, according to Des FitzGerald, vice president of development for Seattle-based Principle Power Inc.

Principle is seeking investors to finance a prototype of its patented WindFloat floating support structure. It is designed to handle a 400-ton tower and a 5-megawatt turbine, with a rotor up to 500 feet in diameter. At commercial scale, Principle anticipates...