LONDON, Dec. 18 — Energy companies plan to erect more than 1,000 turbines off England's coast in a $12.4 billion project to build the largest source of wind energy.

The wind farms, which received preliminary approval on Thursday, would generate as much as seven gigawatts of electricity — enough to supply four million households, or to meet 7 percent of Britain's energy needs. Britain has pledged that 10 percent of its energy will come from renewable resources by 2010.

The Crown Estate, which controls British public lands, including its seabeds, asked companies to submit bids for coastal wind farms in July.

Royal Dutch/Shell, Warwick Energy, Powergen and Total are among companies that won leasing rights of up to 50 years for the project, which involves 15 sites and is expected to start generating electricity in 2007.

The project is vast. Groups of hundreds of turbines will be installed in the shallow waters of the Thames Estuary, in the East Coast area known as the Greater Wash, and off the northwest coast of England.

"This is a massive development for our industry," said Marcus Rand, chief executive of the British Wind Energy Association. "This puts the United Kingdom in the fast lane to becoming a world leader in offshore power generation."

Before they can start building, energy companies need clearance from the public and the government, including environmental regulators. The turbines will be visible from the shore only on very clear days, the companies said, so that public outcry, at least about the view, is expected to be minimal.

The project's biggest obstacle may come in the form of a small waterfowl related to the American loon, the red-throated diver, which feeds in and around some of the sites. The Royal Society for the Preservation of Birds issued a cautionary statement on Thursday, asking the government to make sure the wind farms do not pose a "significant threat to birds."

Little definitive research has been done on the effect of offshore wind farms on the bird population.

"We're in a sort of Catch-22, because we have to prove that this project is not a danger to birds" but there is no project of its size to compare it to, said Peter Crone, a director of Farm Energy, a renewable energy specialist that is one of the winning bidders.

Of course, birds have died after colliding with turbines. "Clearly, birds have been flying into things for hundreds of years, and that hasn't caused any extinctions," said Dr. Mark Avery, director of conservation for the bird preservation group, one of the strongest environmental lobbies in Britain, one that supports renewable energy, including the development of large, offshore wind farms.

But, he pointed out, it might not make great sense "to construct a large number of objects where large numbers of birds are already flying."

Copyright 2003 The New York Times Company

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