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Groundbreaking Tidal Power Plant Officially Unveiled in Eastport
08/25/2010  

The fierce tides of Cobscook Bay have long been viewed as a challenge to mariners. But a Maine-based energy company is now using the movement of those tides to generate renewable power for the U.S. Coast Guard station in Eastport. Murray Carpenter took a boat ride to see the tidal energy turbine in action.

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Groundbreaking Tidal Power Plant Officially Unveil Listen
 Duration:
4:24

Left to right, Congressman Mike Michaud, state Sen. Kevin Raye, Gov. John Baldacci and Chris Sauer

From a boat on Cobscook Bay, about a 15-minute ride from the Eastport pier, Chris Sauer (on right in photo) is pointing out the features of a tidal turbine hanging from the stern of a nearby barge. The turbine looks like the blades of an old push lawn mower, only a lot bigger.

"The turbines are about 20 feet by eight feet in diameter, they are made of 100 percent composite materials made here in Maine -- Bath, Maine. The frame that it sits in came out of Bangor, Stillwater Metals -- it's a combination of steel and composite," Sauer says.

Sauer is the CEO of Ocean Renewable Power Company, which installed the generator. He says this is the largest tidal power plant ever installed in U.S. waters. As a boatload of invited VIPs look on, the turbine is lowered to the water, where it hangs from stout brackets beneath the barge. There, the bay's five-knot tides provide a predictable, clean source of energy.

While tidal water moves more slowly than wind, it provides more force. Tide velocities peak four times a day, and Sauer says one of the company's innovations is developing the systems to harness that power as the turbine spins at different rates.

"We are taking the variable output from our turbine generator unit -- we call it a TGU -- because tidal currents aren't constant, they are constantly varying. So the output varies, and turning that into power that you can plug directly into the grid is a little bit of a trick," he says. "So we have developed the electronic systems to take that variable output and turn it into grid-compatible power."

Sauer is also excited to show visitors some of the sophisticated electronic systems on board the barge which are also tidal-powered. "We track tidal flow, rotational speed, rpms, voltage at different places and then actual power," he says. "We can do historical graphs of power and voltage, tidal flows, etcetera.

The generator uses the power from the turbines to charge large battery packs, which are ferried daily by skiff to the Coast Guard station in Eastport. The battery packs provide almost 20 kilowatt-hours of power daily, about half of the energy needs of the 41-foot search and rescue boat docked there.

It is a small amount of power, a drop in the ocean; it would take 25 such turbines to equal the rated capacity of just one of the wind turbines recently installed on Vinalhaven. But it is a good start, says Coast Guard Captain James McPherson. He has just returned from working on the oil spill response in the Gulf of Mexico.

"We saw what happened when oil is released in the environment. And now we just need to move past that, and 20 years from now, I'm hoping that we'll be looking back at this as just a routine event, you know, you using the power of the tides everyday," he says. "It seems so logical and sensible, and this is a great first step, and I'm glad we are doing it here in Eastport."

The generator could have some environmental impacts of its own. so University of Maine researcher Gayle Zydlewski is studying the turbine to see if -- and how -- it affects fish. Along the way, she hopes to learn more about when and how fish migrate in the bay.

"That's why we are targeting our studies during different seasons. Because in May and June we may see things like alewives and salmon moving into the estuaries for spawning purposes, whereas at different times of year, mackerel and herring may be moving through the bay, in different directions, and they may be using the tide to do that," Zydlewski says.

Among those along for the boat ride are project supporters, like Republican state Sen. Kevin Raye, Democratic Congressman Mike Michaud, and Gov. John Baldacci. Baldacci has been promoting tidal, wave and wind energy, and he says this project shows the possibilities.

"You know, they say seeing is believing, and I think that those who are still wondering and questioning about what we should be doing as a state or a nation needs to come out and believe in it because it is actually happening, it is happening with Maine businesspeople, Maine contractors, it is happening with University of Maine students, graduates of the University of Maine, Maine Maritime Academy, the local community," Baldacci says. "I think what is happening here is a microcosm of what could be happening statewide."

The project cost $4 million, including more than a million dollars of federal and state support. Ocean Renewable Power Company is using the data it is gathering to fine-tune a larger installation in Cobscook Bay, planned for 2011. That system, according to the company, should generate enough electricity to power 50 or 60 homes.




 

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