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Source: New London Day

An idea whose tide has come

Firm studies possibility of harnessing swift currents of The Race in underwater power plant

Posted: January 20, 2009
Originally Published: January 19, 2009

In the endless inrush and outflow of tides and currents through the eastern end of Long Island Sound, Roger Bason sees an untapped energy resource.

Bason and his company, Natural Currents Energy Services, are studying 10 locations within the two main channels, The Race and Plum Gut, for a suitable location for a system of underwater turbines that would generate up to 1,000 megawatts of electricity.

That would be enough to fill 15 to 20 percent of Connecticut's needs. But whether the power would ultimately go to Fishers Island and Long Island, into the New England power grid or some combination of the two is one of many questions to be answered as the project winds its way through the long, complex and uncertain path from idea to reality.

Tidal energy, one of four relatively new types of power generation being proposed for dozens of waterways across the country, is an emerging renewable energy technology that shows much promise, experts say. Wave, ocean current and river current energy are the others. The harnessing of tides and rivers to turn water wheels and other mechanical equipment dates back more than 1,000 years, but technology to turn that energy into electricity emerged only over the last two decades.



The kinetic energy in the tidal flow is captured as the water flows across the rotors, or blades, of the turbine.

As water turns the rotors, they create rotational energy that a generator converts into electricity.

There are two main designs for tidal turbines. They can rotate horizontally or vertically.

Main environmental issues include: effects on bottom-dwelling marine life; potential for killing and injuring fish; effects on migrating aquatic animals; and effects of noise and sediment disturbance.

Initial studies indicate the impact is likely to be minimal “where appropriate care has been taken in site selection and project design.”



”Tidal energy has significant potential,” said Keith Frame, director of new technologies for The Connecticut Clean Energy Fund. “The Race would be a very challenging place to do it and a very lucrative spot to do it.”

In a report filed Jan. 6 with federal energy regulators, Natural Currents noted water speeds of 4 to 7.5 knots through The Race and Plum Gut, an area heavily trafficked by cargo ships, recreational vessels, lobster boats and submarines. Depths range from 101 to 242 feet.

Operating something like an undersea wind farm, the turbine systems would be anchored on the sea floor and turn with the water flow to send energy to a generator that would deliver power into a submerged transmission cable. Bason said the equipment would not interfere with navigation. It would probably be located in New York state jurisdictional waters, he said, but that could change if further study favors a spot in Connecticut waters of the Sound. Towns nearest to the potential sites are Suffolk, N.Y., and New London, Groton, Waterford, East Lyme, Stonington and Westerly, according to company documents.

Bryan Garcia, project director of the Center for Business and the Environment at Yale University, said the potential of tidal and other new hydrokinetic technologies is widely recognized, but there are still challenges to be overcome to make it commercially viable. There is, however, strong public support for developing new renewable energy sources, he said, and the incoming Obama administration is seeking to provide incentives for these projects.

On a section of its Web site promoting the development of renewable energy to reduce greenhouse gas emissions from fossil fuel energy plants, the Union of Concerned Scientists estimates that tapping the hydrokinetic potential of waves, tides and currents in various areas could supply enough power for 67 million U.S. homes. That would be enough to replace the power generated by 22 new coal-fired plants. The scientists' organization called hydrokinetic power “an untapped, powerful, highly concentrated and clean energy resource.”

”The public is ready for these technologies,” said Garcia, of the Yale center.

Headquartered in New Bedford, Mass., Natural Currents has permission from the Federal Energy Regulatory Commission to study The Race and Plum Gut for tidal energy. It plans to submit an application in June for a license to install a small prototype turbine system, Bason said in a phone interview last week. It is the first of many permits the company would need from federal and state regulators.

In the Jan. 6 filing with the Federal Energy Regulatory Commission, the company outlined progress made thus far on analyses of tidal and current speeds at different locations, habitat and geological characteristics and other areas.

”This is a big vision, and we want to roll it out very carefully,” he said. “We're all about sustainable development, green jobs, energy independence, reducing global warming emissions, creating new infrastructure.”

Bason emphasized that his company wants to work cooperatively with lobstermen, fishermen and other users of The Race and Plum Gut so that the all can coexist.

”We're not here to upset the lobstermen,” he said. “We want to find compromises.”

The company worked with the developers of Verdant Power, a prototype tidal energy project on the East River in Manhattan, Bason said, but would employ a different turbine technology at any of the six sites around the country where it is considering installing its equipment. In addition to Long Island Sound, Natural Currents also has permission from FERC to do preliminary work at sites in Alaska, the Hell Gate channel on the East River, Cape Cod canal, New Jersey and Washington state, Bason said. At the New Jersey site, he said, the company is ready to install prototype equipment.



  • To generate 1,000 megawatts of electricity with tidal turbines, Natural Currents would need 100 10-megawatt turbines.
  • Each turbine is about 3 feet by 3 feet by 8.5 feet with helical, curved turbine blades that spin with the tides.
  • One hundred turbines would take up less than 1 percent of the area of the sea floor in the permitted sites in The Race and Plum Gut.
  • The Race is about four miles wide; Plum Gut is less than a mile wide.



The company's timeline for the Long Island Sound project calls for the installation of test equipment by 2010, after it completes studies of marine sediment, the impact of turbines on fish and other marine animals, the existing power connections, discussions with the public and local officials and other steps. The Race and Plum Gut locations are attractive, Bason said, because of the strong current and tidal speeds, the proximity to large energy customer markets and transmission lines and the availability of local manufacturing firms that might be interested in building turbine components for the company.

Natural Currents recently opened an assembly plant for the turbines in New Bedford. An energy engineer and geologist, Bason founded the company eight years ago.

Among local officials who have heard about the project, reaction thus far is generally positive. But they also want to make sure the project wouldn't do undue harm to the environment.

”We're generally supportive of tidal energy, but we need to gather data” on various effects on marine life and recreational and commercial fishing, said Adrienne Esposito, executive director of the Citizens Campaign for the Environment. Her group opposed the Broadwater Energy project, which was also proposed for the Sound but would have relied on a fossil fuel, liquefied natural gas.

Both Southold, N.Y., Supervisor Scott Russell and Dennis Schain, spokesman for the Connecticut Department of Environmental Protection, expressed qualified support.

”This sounds like an innovative project, but we'd want to see that it could be done in a manner consistent with our efforts to protect the Sound,” said Schain.

Bason, for his part, is confident that the environmental impact will be small, especially when compared to the impact of fossil fuel-burning power plants. The Electric Power Research Institute, in a discussion of wave and tidal power on its Web site, called these technologies “among the most environmentally benign electricity generation technologies yet developed.”