Tidal energy project proposed for Sound

Clean, renewable energy in Nantucket Sound using the natural ebb and flow of the tides is being proposed for Muskeget Channel.

A visual of the type of undersea project proposed for the area around Tuckernuck. The use of tidal flows to generate electricity is a technology that is catching on as one of many renewable energy options in the early years of mainstream global warming awareness.

Natural Currents Energy Services, LLC, a Highland, N.Y.-based firm, is proposing to generate three gigawatts of power annually by placing tidal energy generators in Nantucket Sound between Nantucket and Chappaquiddick on Martha's Vineyard. That is about 4.2 times the amount of electricity - around 70 megawatts - flowing to Nantucket right now via two underwater cables.

Calling it the Nantucket Tidal Energy Plant, Natural Currents Energy Services President Roger Bason said that his company is in the preliminary permitting phase of the project that, under ideal review and permitting conditions, would have the tidal generators online by 2011.

Bason filed for a preliminary permit with the Federal Energy Regulatory Commission on June 13 to explore possible sites in the Muskeget Channel and is awaiting the expiration of a 60-day public comment period in mid-August when he expects to get his preliminary permit.

The FERC, which in February generated protocols and parameters for reviewing, permitting and monitoring tidal energy projects, granted a second company, Oceana Energy Company of Washington, D.C., a preliminary permit to explore a location in Vineyard Sound on May 31. Both saltwater hydroelectric power companies are required to file progress reports with the FERC every six months.

When Bason gets his preliminary permit, he can begin scouting his area for the right project location.

"Ideally, we'd like to finish all the preliminaries and public hearings in less than three years and have a plan to move forward," Bason said. "We feel that it will have a very minimal fish impact and would have to be proven by some sort of pilot installation."

Bason said his company would use unidirectional tidal generators, essentially turbines enclosed in short tubes or double-ended funnels, or open rotors anchored to the bottom that would be turned by tidal currents of three to eight knots (2.6 to 6.9 miles per hour). Unidirectional turbines are built to rotate and generate electricity in either direction, switching automatically as the tides change direction.

Because he is in the very early stages of planning this installation, Bason could not say which of four brands of generators he would employ, how many would be placed in the Sound or how many homes would be powered.

"The choice of the generator type is going to be a product of what we find out in detailed studies that we follow, but we do have a pretty good idea of what we want to do there," said Bason.

Although three gigawatts is the output Bason is shooting for, it is tough to estimate how many generators would be installed since Bason said they come in so many different sizes and he has yet to explore his chosen area. Bason's company has or is working on tidal energy projects in New York Harbor, off Long Island and in Florida and is pursuing another installation in the Cape Cod Canal.

Once Bason finds a site he thinks will work in the Muskeget Channel, he wants to deploy 25-kilowatt pilot systems that are enough to power 10 to 12 homes to test the viability of the site. Once satisfied that he has found a site for his installation, Bason would then file with FERC for a license to build and run the tidal energy project. He is banking on a more favorable reception for tidal hydroelectric power generation than Cape Wind Associates is getting for its 130 wind turbines proposed for Horseshoe Shoal because Bason's generators will not be heard or seen, and are expected to be fairly benign in terms of environmental impact on the bottom of the channel.

"The thing that people need to be aware of is when the energy policy isn't working, it needs to be changed," said Bason. "Maybe to benefit from these high energy prices we need to look at options

and opportunities for change." I