Edgartown's tale of tidal currents: Muskeget Channel energy farm
On the night of Sept. 11, 2007, Karen Fuller made a dash to the airport with a Federal Express package full of papers. It's what she does, as the administrative assistant to the Edgartown selectmen and the town administrator. She meets the deadline. But this was no ordinary deadline.
When that package arrived at the Federal Energy Regulatory Commission (FERC) in Washington, D.C., Edgartown had met a critical deadline by a matter of hours.
"It was amazing, right down to the wire," said Edgartown selectman Art Smadbeck.
"Absolutely awesome, what an incredible job," said Edgartown resident Kitt Johnson,
Someday, a decade or so in the future, residents of Martha's Vineyard might look back on Ms. Fuller's race to catch that flight as the first leg of a long and complex process that led to abundant, inexpensive electricity, enough power to light, heat, and cool much of the Island.
Inside that FedEx package was an 82-page application for a preliminary permit that would allow the town exclusive rights to study promising new technology that can pull power from ocean tides.
Last month, Edgartown received notice that FERC has accepted the town's application for a preliminary permit to study a tidal energy project proposed for Muskeget Channel, the area between Martha's Vineyard and Nantucket.
The application is the result of hundreds of hours of work, completed on short notice, with the deadline looming all the while. Mr. Johnson, retired from a senior management position with the international consulting firm Arthur D. Little, Inc., led the project.
Edgartown is now competing for the preliminary permit with Natural Currents Energy Services, LLC, which applied to develop plans for a project in the same part of the ocean.
"We found out that a private company had very quietly tried to gain access," said Mr. Smadbeck, "which would have precluded the Island from using it. Edgartown had rights in this area that superseded the rights of a private company, and indeed the federal government does give municipalities special rights if they apply." He also emphasized that while Edgartown is applying for the preliminary permit because it has legal standing, he envisions the project will supply power for all the Island towns.
If eventually granted, the preliminary permit only allows evaluation, including economic analysis, preliminary engineering plans, and a study of environmental impacts. It does not grant rights to alter the area, or build any generators.
A preliminary permit is a tiny but crucial step, because it would give the applicant exclusive rights to the area for three years. "They have a priority over that site," said Celeste Miller, a spokesperson for FERC. "No one else can come in and develop."
The next step in the process is a period of public comment, which opened December 18, the day the application was accepted, and continues for 60 days.
After that, the regulators will decide who gets the preliminary permit.
Turbines and technology
The project proposed by Edgartown is known as in-stream tidal generation, a way to harness the energy of the tides.
These "tide engines" are similar to more familiar wind turbines, except they work underwater. In general, tides generate more concentrated energy than wind, so underwater turbines must be built stronger and more durable than wind turbines. But they can also be built smaller, turn slower, and be located closer together.
Experts agree that tidal power generation has many advantages over power from fossil fuels, or solar or wind power. Tides are easily measurable, easily predictable, and unfailingly consistent. Underwater turbines produce no emissions, and some designs operate completely underwater, invisible from the shoreline.
There are also drawbacks. Concerns have surfaced about the affect on fish populations, on marine navigation, and on the sea floor where the turbines would be anchored. While the technology is still in the early development stage, it is expected that maintenance of underwater turbines will be a significant cost.
Another obstacle is geographic. There are relatively few locations throughout the world where tides are strong enough to generate economical power, near enough to the market where the power will be used, and near enough to ports with marine facilities to provide support. Muskeget Channel has been identified as one location with strong potential.
Muskeget Channel is a six-mile wide stretch of open ocean between Martha's Vineyard and Nantucket. The tides ebb and flow between Nantucket Sound and the Atlantic Ocean through this channel.
Most of the area is relatively shoal, but about 1.5 miles off Wasque Point, an underwater trough less than 1,000 feet wide drops off to a depth of 135 feet. The optimum depth for underwater turbines will depend on the kind of technology used, but the characteristics of Muskeget Channel may make it possible to extract energy from both shoal and deeper waters.
If the preliminary permit is granted, the next step will be gathering data to evaluate the site. Estimates about the amount of power that could be produced, and how much it will cost, are theoretical only.
"I found many predictions, and no hard data," said Mr. Johnson., who believes there may be several points in Muskeget channel where peak currents exceed five knots. If turbines can be located in these areas, theoretically, they could produce raw power at a cost below the comparable cost of electricity now mostly generated by a mix of coal, gas, and nuclear-fueled plants.
"Edgartown is hopeful that the final analysis will show that the cost of producing electricity with the tide engines would be around 10 cents per kilowatt hour, which would be a significant savings over the current price," said Mr. Johnson. "Since this would be a fairly fixed price, the savings would only grow over the years if electricity prices continue to increase at the rate that fuel prices have been going up. If we can start to lock in a reliable supply of electricity, that's such a benefit to the town."
Evaluating the site will be costly. Mr. Smadbeck is hopeful that researchers at the University of Massachusetts Dartmouth can partner with the town to conduct the necessary mapping and measurement of Muskeget Channel.
"We have to interest people with money, to collaborate with us," said Mr. Smadbeck. "We have to perform. That's where the money comes in. The first study is probably going to be somewhere between $100,000- 250,000. This is no easy task. This isn't like, we all ride out in a boat and drop a line down and see how fast the current is going. This is really serious stuff with some serious money attached."
Light in the tunnel
Edgartown is a long way from generating the first watt of electricity from the tidal currents off its shore. There may be light at the end of the tunnel, but the town is not even in the tunnel yet. There are significant regulatory, technological, and environmental hurdles to overcome. Even with all the caution, however, the possibilities are evident in the enthusiasm of those working toward the tidal energy project.
"This is the beginning of looking at alternative energy for the whole island," said Mr. Smadbeck. "The technology is coming together with the needs at the same time. The goal would be to have Martha's Vineyard have all of its electricity needs supplied through some kind of renewable energy source. If we set it up right, it could be quite a demonstration project."