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PRI's Environmental News Magazine

High Tide for Tidal Power?

Air Date: Week of July 8, 2011

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The high-tech blades of the Energy Tide 2 turbine spin in the water as tides come and go. The zero-emissions electricity has so far shown very little environmental impact. (Photo: Jeff Young)

Is it high tide for tidal power? Clean energy entrepreneurs are exploring ways to turn the flow of the tides into electricity in the Bay of Fundy. The bay, between Maine and Canada, has the world’s highest tides. But Living on Earth’s Jeff Young tells us the Bay’s history also shows just how hard it can be to make tidal power work. Photo: The high-tech blades of the Energy Tide 2 turbine spin in the water as tides come and go. The zero-emissions electricity has so far shown very little environmental impact. (Jeff Young)

Transcript

GELLERMAN: In the quest for clean energy scientists look to the power of the wind, the sun, the deep earth and even the moon—or more specifically, the moon’s gravitational pull on our oceans. The motion of the rise and fall of the tides carries enormous potential energy to the coasts twice a day like clockwork. However, harnessing that power has long proved problematic. Many have failed. But Living on Earth’s Jeff Young visited some energy entrepreneurs who think they can turn the tide on tidal electricity.

[SOUND OF WAVES AGAINST DOCK]

YOUNG: The barge-like craft moored to a dock in Portland, Maine, looks like some modern version of a sternwheel paddleboat. Hydraulic arms hold a massive cylinder of blades ready to go in the water. But this boat isn’t built for speed, it’s built for power — tidal power. It’s the creation of Chris Sauer and his Ocean Renewable Power Company.

  

Chris Sauer and his company’s Energy Tide 2, which was developed with some help from the federal government. Sauer hopes the Dept. of Energy will continue its modest support of tidal power. (Photo: Jeff Young)

SAUER: This is our baby, this is the Energy Tide 2. This is the largest ocean energy device ever deployed in U.S. waters.

YOUNG: Let’s have a look.

SAUER: Come aboard!

[SOUNDS OF WALKING ONBOARD BOAT]

YOUNG: The Energy Tide 2 is normally anchored near Eastport, in an arm of the Bay of Fundy called Cobscook Bay. Sauer towed it to Portland for a national convention on ocean energy. He shows me to the boat’s business end, the high tech composite blades curved inside a turbine generator unit, or TGU.

SAUER: When it’s fully deployed it’s directly under this axle right here. And it’s about 15 feet from the top of the water to top of the TGU, and then it’s locked into position and it just sits there. And as the tidal currents come it starts to generate electricity. And then of course the tide reverses and comes the other way and does same thing. On an average basis we’re generating about 18 to 20 hours a day.

YOUNG: A small cabin crowded with electronics and monitors converts the power and keeps track of what’s happening underwater. The unit can generate 60 kilowatts of power and that’s been going to a coast guard station, the country’s first federal facility to use tidal power. But primarily, this is a research project. Sauer says in a year of operation it’s shown virtually no impact to fish or other marine life, and it’s proved that the tides can predictably generate power that could be plugged into the grid. Now Sauer wants to scale up.

SAUER: The next step is our turbine generator unit is going to get a little bigger, instead of two turbines it’s going to have four turbines. It’s going to be about twice as long, but it’s going to put out three times the power. So instead of a design capacity of 60 kilowatts it will be 180 kilowatts. And we hope to get that in the water and connected to the grid by the end of the year. That’s our plan.

YOUNG: Sauer says the project has also proved tidal power can generate jobs. The company has provided jobs for 100 people in Maine, people like Darrell Speed who had been laid off.

SPEED: Honestly I was at the stage where I was going to have to look to go outside of Maine. I was born and raised here, want to stay here, but, you know, it was coming down to that.

YOUNG: That’s when Speed saw an ad for ocean renewable power. He had no idea what it was about.

SPEED: Well, quite frankly I didn’t care at the time. I needed a job. Like I said before, I wanted to stay in Maine. But since I’ve gotten here this company, you know, it’s a company about creating jobs but also a company about creating a sustainable energy resource for the United States. And it’s renewable. The tides go, ebb and flood every day. You can set your watch by it. Now, will we be 100 percent able to replace all our energy resources? No. But we’re part of the answer – a big part of the answer.

YOUNG: At least three other companies are trying to harness the tides in these waters using similar technology. On the Canadian side of the Bay, Mark Savory is vice president for Nova Scotia Power, the provincial utility. He hired an Irish company called Open Hydro to supply a tide turbine that looks like the front of a jet engine. The blades are inside a disc housing the magnets of the generator. Savory’s crew moored it to the bay’s floor in 2009 then pulled it up a year later, to an unpleasant surprise.

SAVORY: We lost the blades off of it. It’s like we just purely overloaded it. So other than the fact that there’s no blades on it, it looks almost like the day we put it in.

YOUNG: (Laughs) So just stripped out the blades. I imagine you reporting back to your boss and saying, ‘I’ve got some good news and some bad news here!’

SAVORY: That was exactly my story last year: I have good news and I have bad news. Bad news is, no blades. Good news is, boy there’s a lot of energy there. A lot more than we would have thought.

YOUNG Savory’s not giving up. Nova Scotia Power estimates it might be able to get two gigawatts of electricity from the tides, about 15 percent of the province’s annual power consumption. Other areas like Cook’s Inlet in Alaska and the Pacific Northwest coast have potential — even New York’s East River has a tidal power test underway. But just how much can we harness from such harsh environments? That’s what Dr. Robert Thresher is trying to figure out. Thresher is a research fellow at the National Renewable Energy Laboratory in Colorado. He’s worked with wind power since its early development in the 1970s. Now he’s researching tidal power and finds the two are really quite similar.

THRESHER: They absolutely are. A lot of the basic understanding and engineering fundamentals with which you use to design a good wind turbine, you would use exactly those same principles to design a tidal turbine. Tidal power is, if you want to think of it that way, it’s just a different fluid.

YOUNG: Wind power took about 35 years to go from prototypes to commercially viable power. But Dr. Thresher says tide power could develop much faster.

THRESHER: In my opinion, the tidal power stands on the shoulders of wind power. I predict that we’ll start to see some tidal power on grid within two or three years, and that it’ll grow over next five to 10 years to become basically a practical technology.

YOUNG: Thresher’s rough guess is that tidal power and other forms of ocean energy could eventually provide five to 10 percent of U.S. electricity demand. But that will largely depend on how much the government is willing to do to help make it happen. One reason Europe is far ahead in tidal power development is because many EU policies encourage clean energy. Will the do the same US government ? Some lessons lie in the history of the Bay of Fundy. People have been trying tidal projects here without success for nearly 80 years but they keep coming back for some reason.

WOODARD: Easy answer: it’s the world’s highest tides in the Bay of Fundy.

YOUNG: That’s Maine writer and regional historian Colin Woodard who describes the phenomenal power of Fundy’s tides, which can rise up to 50 feet.

[SOUNDS OF BAY OF FUNDY TIDAL FALLS]

WOODARD: It looks like a reversing river flowing, the entire ocean is moving rapidly before your eyes when the tides are moving. There’s the largest whirlpool in the western hemisphere forms as the tides collide, it’s large enough to pull a small boat down. It’s a very dramatic thing to look at.

[SOUND OF WATER DRAINING]

WOODARD: The amount of energy involved is absolutely enormous which of course makes it attractive to those wishing to generate electricity from tides. The original plan was cooked up by a fellow named Dexter Cooper, who was a hydroelectric engineer who had a summer place on the bay.

[OLD NEWSREEL SOUND]

YOUNG: Cooper’s plan is portrayed in this 1936 March of Time newsreel.

[NEWSREEL: Why not, reasoned Cooper, harness this tide, bottle it up and send it through a turbine to generate cheap electricity?]

WOODARD: So that’s where the idea first came from and by happenstance his next door neighbor was the future president, Franklin Delano Roosevelt, which facilitated, later on, the project being taken up by the federal government.

YOUNG: Roosevelt approved 10 million dollars to start a series of dams on the Passamaquoddy Bay. But critics in Congress balked at the project’s price.

President Roosevelt inspects a model of the proposed Quoddy Dam tide power project. FDR pumped 10 million into the project before Congress pulled the plug on it. (Photo: courtesy National Archives)

  

WOODARD: This appeared to be a gigantic boondoggle in that it was going to cost a lot of money. So that economic argument ultimately was winning the day in Washington and within a year or two it was pretty much unplugged by skeptics in Washington.

[NEWSREEL: Relics of a great boom lie scattered drearily about. For here the federal government started to spend many millions of dollars to build a gigantic power dam. Started, and then suddenly stopped.]

YOUNG: That history lends a sense of déjà vu to the current tidal power projects. In 2005 the U.S. Department of Energy started a small ocean energy program called Marine Hydrokinetics, which has put about 100 million dollars into research and matching grants to support tide and wave energy. Tidal power developer Chris Sauer says that DOE program is crucial. But the austere budget environment in Washington could put it on the chopping block.

[QUIET DOCK SOUNDS]

SAUER: This is a very minor amount of money, it’s a drop in the bucket compared to what is given to the oil and gas and coal and nuclear industries, but it’s critical for us at this point. That funding is unfortunately drying up just at a time when we need it the most.

YOUNG: Support for tidal energy seems to rise and fall like, well, the tides themselves. Developers like Sauer are hoping that this time interest won’t ebb too soon. For Living on Earth, I’m Jeff Young in Portland, Maine.

 

 

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