Marine power
Underwater windmills to be powered by St. Lawrence River
Last Updated April 18, 2008
By Mary Ann Colihan
The St. Lawrence River at Cornwall, Ont., is to be the proving ground for a Canadian company's underwater turbine technology that promises to generate a constant source of electricity from the fast-flowing current.
The turbines from Verdant Power Canada look and function like underwater windmills, only they move at a sedate 32 revolutions per minute. The Cornwall Ontario River Energy (CORE) Project is a four-year, two-phase plan with an initial goal to develop 15 megawatts of power.
Trey Taylor is the president and founder of Verdant Power, which was incorporated in Canada shortly after he re-located to Burlington, Ont., from New York City. "I have lived here for over a year and a-half to develop these technologies," he says.
Verdant Power Canada's power-generating turbines look and function like underwater windmills, only they move more slowly, spinning at about 32 revolutions per minute. Verdant received a $2.2 million grant from the Ontario government’s Innovation Demonstration Fund last week to help it further fine-tune the technology. The company says the CORE project will demonstrate the commercial viability of the company's three-blade Free Flow Turbine.
Pilot testing
A similar pilot project is under way in New York City’s East River, harnessing tidal flows. The East River is a tidal estuary that connects Long Island Sound with the Atlantic Ocean, and tides flow twice per day in both directions. To date, it's the world’s largest demonstration of tidal power tied to a power grid.
Getting the turbines to provide a reliable source of power has not been smooth sailing, though. The initial five turbines Verdant sank off Roosevelt Island and the Upper East Side of Manhattan had to be hauled out of the water because their rotors, or turbine blades, shredded. But to that point, they did produce 40 megawatts of electricity over 7,000 hours of operation — a world record for tidal power.
"The East River currents were stronger than our original estimates. There were blade failures," Taylor says. "The new rotors will go back on in May. We saw it as a blessing in disguise. Every single rotor broke in the same spot and caused a cascading effect — we learned that we had arrayed them wrong in the water."
New rotors have been tested at the National Renewable Energy Lab in Colorado and will be made of aluminum magnesium instead of fibreglass around steel.
Taylor says another lesson learned from the East River trials was that for the rotors to deliver peak performance, the turbines have to be spaced, or arrayed, in a specific pattern. Taylor says the way the turbines are arrayed helps them shed excess load when necessary — or go with the flow and the force of the stream.
Verdant Power plans to deploy a new type of frame in the St. Lawrence as a result. Taylor says the new frame design is more stable and will arrange the turbines in the stream to make them more productive.
"The way we first installed them in the East River, we put a single post into bedrock with three turbines on each," says Taylor. "Now we will separate the turbines on a wide frame in the shape of a triangle. We can raise or lower them for installation."
Taylor says this means the company won’t incur the cost of drilling. There will also be less environmental impact to consider, since the base will not be permanent.
Location, location, location
Careful consideration went into the location of the project. Logs or underwater debris can damage the turbines, for example, but Taylor thinks the downstream location from the Moses-Saunders power dam should block the worst hazards.
"We are in the St. Lawrence River near where it takes a turn — not in the Seaway," says Taylor. "There is no fishing in the first place in this current. For boating, the [highest] tip of the rotors are 10 feet underwater and marked by buoys."
The Saint Lawrence River at Cornwall is channeled around many islands. Cornwall Island, one of the largest, is part of the Mohawk Territory of Akwesasne, located south of the City of Cornwall, and straddles the borders of Ontario, Quebec and New York state.
"The Akwesasne on Cornwall Island were the first group we met with to get permission for the test phase," says Taylor.
Henry Likkers is a biologist, a member of the Seneca nation, and the director of the department of the environment for the Mohawk Council of the Akwesasne. He says before Verdant can put anything in the St. Lawrence it will be subject to a Mohawk Council environmental assessment.
"The river is ours. We have jurisdiction — although the government would disagree," says Likkers. "Before anything can go in the river — even the dummy turbines — we require that they do an environmental assessment to show there is no impact."
Taylor says Cornwall has already taken it on the chin when it comes to environmental issues. Cornwall is listed as a Great Lakes Area of Concern (AOC). Concerns over fish, wildlife, sediment and other issues will be addressed later in this study when the company applies for a permit to generate power and will be subject to an environmental assessment. Taylor says the company collected a volume of data for regulators in New York, especially about how fish interact with the turbines.
A pre-production model of Verdant Power's electricity-generating water turbine is mounted above ground for testing at an assembly facility in Troy, N.Y., in this April 2006 file photo. (Verdant Power) Likkers says the Council has worked with Verdant from the beginning to mitigate environmental impact.
"We can help Verdant with the traditional Mohawk knowledge we have of the river," he says. "For example, our fisherman can steer them away from the sturgeon."
Likkers adds that the East River is an estuary with fish like the striped bass, and may not be comparable to the St. Lawrence. He says there may be mechanical issues from Great Lakes invasive species like zebra mussels that can cause problems for the turbines.
He says this is why the Mohawk Council environmental assessment, which harmonizes with provincial and federal environmental assessments, can help move the project along safely. Verdant is using underwater videotape from the St. Lawrence to help pinpoint issues with the Mohawk Council.
Other project team members include the City of Cornwall, St. Lawrence College, St. Lawrence River Institute and Natural Resources Canada.
Development plan
Taylor expects the new frames will go into the river this summer with "dummy turbines." Then the company will apply for a licence for 5MW of power with a potential to go to 15MW. One megawatt of power can generally supply the energy needs of 1,000 homes.
"There will be no issues getting on the local distribution grid but how to get on to Hydro One is yet to come," says Taylor.
There are three Verdant employees in Canada and 15 more in the U.S., Taylor says, and the company is hoping the projects will generate buzz around its technology and spur growth. "Our goal is to have 10 people in Canada."
A virtual tour of Verdant’s tidal power project in the East River is on display at The Global Marine Renewable Energy Conference that opened in New York on Thursday, an event that brings together more than 300 industry experts in marine renewable energy. The federal government is a major sponsor of this conference, hosting a Canadian reception called "Canada’s Ocean Energy Momentum, Energizing a North American Opportunity."
Taylor estimates that Canadian rivers, ocean tides and man-made channels could produce 15,000 megawatts. Taylor says this will be needed to replace power plants slated to close in the coming years. "We have this wonderful notion that we should close coal-fired plants here in Ontario."
The Ontario government has a 2014 deadline to phase out coal-fired generation. Its $2.2 million investment in marine renewable energy is one step toward meeting that goal.
The boundary waters of the St. Lawrence River between Canada and the United States are on a growing list of places trying to grab energy from open, free-flowing water. The Bay of Fundy, with tides that reach 16 metres or more, is also in the early stages of testing marine power technology.
"Verdant Power is creating solutions for a world that is looking for ways to tackle climate change and move towards non-carbon based, more sustainable forms of energy," says John Wilkinson, Ontario Minister of Research and Innovation. "They are developing a solution that not only works right here in Ontario, but one we can export around the world."
But first they need to produce power over the long haul. The mighty St. Lawrence is another opportunity to see if Verdant Power’s turbines are as dependable as the tides.
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