Power Research Institute Challenges Practicality of Tidal Energy Project

Gazette Senior Writer

Engineering analysis has raised questions about the practicality of a proposed tidal energy farm near the Middle Ground in Vineyard Sound.

Roger Bedard, ocean energy leader at the Electric Power Research Institute in Palo Alto, Calif., said the tidal flow through the Sound is not fast enough to make a tidal turbine energy project feasible.

Mr. Bedard said water bodies, regardless of size, need a median tidal flow of at least five or six knots to make submerged tidal devices work. But he said the flow in that area of the Sound is about three knots.

An April study by the research institute into six possible tidal energy sites in Massachusetts dismissed two Vineyard Sound sites as lacking sufficient power density.

One site, north of Norton Point, is in the same area proposed for a tidal energy farm by the Massachusetts Tidal Energy Co. of Washington, D.C. The other is north of West Chop.

Massachusetts Tidal has proposed placing up to 150 submerged propeller units between Martha's Vineyard and the Elizabeth Islands in Vineyard Sound.

The company has applied for a preliminary permit from the Federal Energy Regulatory Commission to build the experimental underwater energy farm between the southwestern corner of Naushon Island, Nobska Point in Falmouth and an area west of Lake Tashmoo in Vineyard Haven.

Mr. Bedard, of the research institute, also questioned technical aspects of the plan put forward by the company in its application to the commission.

Told that Massachusetts Tidal had proposed using an array of turbines that each could generate between 500 kilowatts and two megawatts of power, Mr. Bedard laughed.

"There's no room in the Vineyard Sound for those things," he said. "They don't know what they're talking about."

Massachusetts Tidal is a subsidiary of Oceana Energy, a company incorporated in Delaware to pursue tidal energy projects. Vineyard Sound is one of eight sites around the United States coast for which Oceana subsidiaries have applied for preliminary federal energy permits.

Oceana has obtained a preliminary permit for one of the sites, at the Golden Gate Bridge outside San Francisco.

Other sites sought by Oceana subsidiaries include the Piscataqua River in New Hampshire, the Kennebec River in Maine, the East River in New York and the Columbia River in Oregon.

But the April study by the research institute found that the Muskeget Channel between Martha's Vineyard and Nantucket is the best site in Massachusetts for tidal energy generation.

The study calculates that tidal devices could extract a mean average of 2 megawatts from the channel. The next highest mean average came from the Cape Cod Canal, which essentially is closed to tidal energy projects because of the canal's mission as a navigable passage.

"We knew about the other site," said Daniel Power, president of Oceana Energy, speaking of Muskeget. "We might have made a mistake. If it's not a good site, we have seven other sites."

Mr. Power said Oceana had reasons for not choosing the Muskeget site, including the lack of nearby power lines or transformers.

In April, Massachusetts Tidal filed for a three-year preliminary permit for a tidal energy project in Vineyard Sound between the Elizabeth Islands and Martha's Vineyard.

Tidal turbines would be placed in two sections, to the north and the south of the Middle Ground and Lucas Shoal. The devices, whose rotating propellers would range in diameter from 20 to 50 feet, would be anchored to the sea bottom in navigable waters between 40 and 75 feet.

In the application, the company proposes a buildout of between 50 and 150 tidal in-stream energy conversion devices, along with a transmission line that would connect the devices to the power grid near Nobska Point in Falmouth and/or Lake Tashmoo in Vineyard Haven.

The company claims each device can provide power to about 750 homes. Based on figures included in the filing, the built-out tidal farm could generate between 25 and 300 megawatts at any given moment. That puts the potential generation capacity of the farm at about two-thirds of the estimated maximum output of the 130-turbine wind farm proposed for Horseshoe Shoal in Nantucket Sound.

A 60-day comment period now is under way, after which the regulatory commission will decide whether to grant the company the permit.

In its filing, Massachusetts Tidal said the institute is researching the nature of the devices in a study titled EPRI North American Tidal In Stream Energy Conversion Project.

But Mr. Bedard, the principal author of the study, who has been investigating tidal energy generation for the past two and a half years, said he has never heard of the company.

"Where did they come from?" he asked. "I think it might be people who want to make a buck."

He said members of the company obviously have read the institute's publicly available information on tidal energy, especially given the company's adoption of the institute's descriptive term for the devices, including the use of the acronym TISEC.

The TISEC term was the winning entry in a contest that Mr. Bedard ran among his colleagues for a name that would set the tidal devices apart from traditional hydroelectric equipment. The prize was a bottle of wine.

The research institute, founded in 1973, describes itself as an independent, nonprofit center for public interest energy and environmental research.

Mr. Bedard, who holds a master's degree in mechanical engineering from the University of Southern California, has worked as business development manager at the Electric Power Research Institute since 1997. He first evaluated wave energy conversion devices more than 25 years ago.

Mr. Power said he has enormous respect for the research institute, but he also said Oceana, an offshoot of the Climate Institute, a 20-year-old nonprofit based in Washington, D.C., has been deeply involved over the past two and a half years in the study of tidal energy potential.

The Climate Institute describes its mission to protect the balance between climate and life on earth. Mr. Power said the institute, among other projects, has helped American military bases to conserve energy use.

"If he doesn't know who we are, how can he say things like that about us?" Mr. Power asked. "And another question: what's wrong with making a buck or two?

"If I wanted to make a buck, I'd invest in ExxonMobil," Mr. Power said. "This is a really hard way to make a buck."

TRC Environmental Corp. of Lowell is advising Oceana on the preliminary permits for Vineyard Sound and the other sites. Jeffrey Brandt, a project manager at TRC, said the permits, if granted, only give Oceana's subsidiaries a priority in researching sites to assess their suitability.

In its filing, Massachusetts Tidal anticipates spending between $1 million and $4 million on studies during the preliminary permit period. The company would have to secure a series of regulatory approvals from other agencies as well as a license from the energy commission before building the project.

"Roger's question on whether it's feasible - that's why we're doing this, to see if it is feasible," Mr. Brandt said.