When it comes to renewable energy production in this part of the world, wind has been stealing the show.
The governor of Maine and the premiers of New Brunswick and Prince Edward Island are big boosters and wind farms have been erected from Mars Hill to PEI’s eastern cape using off-the-shelf technology. PEI plans to use wind to charge hydrogen fuel cells to kick the fossil fuel habit, while there’s talk here of building offshore wind farms, much as Denmark has.
But under the radar and beneath the waves, a rival technology has been taking shape: “in-stream” turbines mounted to the seafloor and spun by the Bay of Fundy’s massive tides. Unlike older tidal technology, the new devices don’t require dams and promise to generate power unseen and unheard from the surface, and with little or no ecological damage.
Tidal power is taking two significant steps forward this fall. By the time you read this, an Irish company will have set a six-story tall device on the floor of Nova Scotia’s Minas Basin, where tides reach 53 feet, the world’s tallest. And in early December, a Portland-based company plans to deploy what they say is the largest tidal turbine ever placed in U.S. waters off Eastport’s Cobscook Bay shore.
“Everything except the power electronics and the generators are being manufactured in Maine,” says Chris Sauer, president of Ocean Renewable Power Co., Ltd, which will suspend their 60 kilowatt device from a barge in the channel near Shackford Head in Eastport. The dual turbine unit will charge batteries for use by the local U.S. Coast Guard station.
But the Minas Basin project has stolen much of the attention on account of its size and government backing. After an extensive environmental and technical review, Nova Scotia’s provincial government designated the site near Parrsboro, Nova Scotia for the testing of three rival devices, all of which will share monitoring and distribution infrastructure and a soon-to-be-constructed visitors’ center.
The first of the devices-a 30-foot wide, 16-fin OpenHydro turbine mounted on a large steel frame-was to be deployed November 10 or 11 and is expected to deliver a megawatt of power. Two competing designs-from UEK of Annapolis, Md. and Clear Current of Vancouver, B.C. -are to be deployed next summer.
The devices are to be mounted to the seafloor well beneath shipping traffic and will be connected to the provincial power grid via underwater cables. “There’s so much energy coming up that channel, it’s quite remarkable,” says John Woods, vice president of Minas Basin Pulp and Power, which is building the shared infrastructure and has partnered with UEK to test their technology. “I have confidence we’ll be successful.”
The three designs at Minas Basin all loosely resemble the fronts of oversized, slowly spinning jet engines. Each features a multi-finned fan mounted in a rounded cowling which can turn in either direction depending on which way the tide is moving.
The turbines Ocean Renewable Power Co has been testing off Eastport work on the same principle, but feature long helix-shaped fin assemblies that resemble the blades of an old-fashioned push lawnmower, only many times larger and with the butt ends exposed to the current. The company tested a smaller-scale prototype in Eastport’s Western Channel for much of 2008, a device that now sites in front of the Husson University Boat School, where the devices are assembled.
“We’ve shown the technology works, and with the new device we’re using less steel and wood and more composite materials and a generator casing we believe will have less drag,” says Bob Lewis, general manager of the company’s Eastport office, as he points out the very un-hydrodynamic generator box on the original prototype.
Tidal power has a big advantage over wind energy: the world’s moon-driven tides may be variable, but they are entirely predictable both in terms of timing and force, allowing utilities to know years in advance exactly how much power will be generated at a particular time. But unlike wind turbines, tidal devices are still in the development phase, with designs needing further testing before they will be ready to market.
“There are a dozen different technologies out there and they’re all still in the infancy stages of their development,” says New Brunswick’s energy minister, Jack Keir, whose province has moved aggressively to develop wind, liquefied natural gas, and expanded nuclear power to feed the U.S. Northeast’s thirst for energy. “When you’re building a 200-megawatt wind farm you can buy the equipment right off the shelf and you know what you’re getting. Tidal power is not there yet.”
Tidal power also has to prove what most have assumed: that devices will have no discernable effect on the environment or fish populations. Mr. Sauer says video monitoring during the year-long testing of their prototype indicated marine life never attempted to enter the turbines. “Fish can sense a sold object ahead and appear to swim around it,” he says.
Not everyone is convinced, least of all Mike Dadswell, a professor of biology at Acadia University in Wolfville, Nova Scotia, which is located near the Minas Basin test area. In July he wrote Nova Scotia officials that the test project there had the potential to kill large numbers of fish that migrate to the head of the Bay of Fundy. “Tidal energy will not be ‘Green Energy” but rather ‘Red Energy’ from the blood of its victims,” he wrote.
“It’s literally impossible to turn a blade in the water and not kill, maim, or harm some fish,” says Dadswell, who has conducted extensive monitoring of fish kills at an old-fashioned dam-based tidal power plant at Annapolis Royal, Nova Scotia. At that 25-year old facility, sturgeon, herring and other fish wishing to travel to and from the Annapolis River are forced to swim through concrete tubes and the spinning generator blades, which kill by impact and pressure changes.
He says the Minas Basin turbines operate on the same physical principles and will also kill many of the fish that swim through them. If 200 to 300 devices are eventually deployed as supporters hope, the damage could be devastating to fisheries throughout the Bay of Fundy. “The fish aren’t forced to go through the turbine there, so it all comes down to fish behavior, whether fish approaching these machines will know to turn away,” he says. Proponents say Dadswell’s conclusions drawn from an old dam-based system don’t apply to the new devices, which fish are free to swim around. “With these devices there’s no sucking and none of that-the physics are totally different than at Annapolis Royal,” says Sauer. “You have a little itty-bitty piece of equipment in a huge area of water with no physical pressure pulling things into it.”
Nova Scotia officials say the point of testing the devices is to determine if there are any baleful effects. “To answer any of these questions, we have to go out and have this project tested in the real world because we’re not going to get the answers in the conference room,” says Nova Scotia Environment Minister Sterling Belliveau, who was a fisherman for three decades before entering politics. “We are doing this with a very cautious approach and we can shut it down immediately if there are any environmental effects of any kind.”
-Colin Woodard is an award-winning journalist and author of The Lobster Coast, Ocean’s End, and The Republic of Pirates. www.colinwoodard.com