Historic first as N.S. tames Fundy’s tides, feeds power to electrical grid

“If we’re able to harness the tides here, it creates a tremendous opportunity for this renewable source of energy throughout the world.”

Rhetoric aside, the underwater turbine developed by Cape Sharp Tidal is just a test model that can generate two megawatts of electricity — enough to supply only 500 homes.

Still, it is an impressive machine by any standard.

At 1,000 tonnes, the cylindrical behemoth stands about five storeys tall, with 10 blunt-nosed blades converging around a circular opening. It is anchored on the seabed at the eastern end of the bay in the Minas Passage, a five-kilometre-wide channel near Parrsboro, where the crushing currents can travel at five metres per second.

“The amount of water that flows through there every day amounts to a larger volume than that produced by all of the rivers in the world, combined,” said Ray Hickey, a local resident and chief operating officer for the Cumberland Energy Authority.

“When you stand there, you can see it and you can hear it. This massive flow of water is just churning through this small passage … It look like a violent body of water with a lot of disturbance in it. It can be a very loud rumble.”

Harnessing the tides has been a work in progress since the 1600s. Various technologies have produced limited success. In 1984, a form of hydroelectric dam was built at Annapolis Royal, N.S., but the small, 20-megawatt plant remains only one of three tidal plants in the world.

In 2009, OpenHydro and Nova Scotia Power deployed a 400-tonne tidal turbine in Minas Passage, only to see it shredded by the currents.

“I think they learned a lot from the first one,” said Hickey, whose organization promotes and develops renewable energy for Nova Scotia’s Cumberland County. “That one, as far as we know, was destroyed right away.”

The new turbine withstood a particularly punishing initiation with last week’s so-called super moon producing some of the highest tidal flows in years.

“That really tested the turbine,” said Christian Richard, vice-president of special projects with Halifax-based Emera Inc. “The turbine that we installed some years ago, from an engineering perspective it was a learning experience. It gave us an appreciation of the strength of the flows.”

The latest turbine is similar to a machine that has operated off Scotland for about 10 years, and it is virtually identical to a relatively new turbine off the coast of France.

The partnership behind Cape Sharp includes Emera Inc. and OpenHydro, a subsidiary of a French conglomerate that specializes in naval defence and energy. Its two-megawatt turbine was lowered to the bottom of the bay two weeks ago.

A second test turbine will be installed in the bay next year. Cape Sharp’s project is one of five aimed at testing different turbine technologies.

Once completed, Cape Sharp’s four-megawatt demonstration project will use a fraction of the 7,000 megawatt potential of the Minas Passage, the government said.

“From a provincial and Canadian perspective, there’s a lot of energy there to be tapped into,” said Hickey. “And it’s all renewable, green energy. So it’s a really big deal for a province that depends on coal. If it’s successful, it could really reduce our dependence on fossil fuels.”

The project, which has employed about 300 people, is expected to displace the need to burn about 2,000 tonnes of coal for the province’s energy needs. That will eliminate about 6,000 tonnes of greenhouse gas emissions — the equivalent of taking 1,000 cars off the road each year, the government said.

However, the project has its share of critics.

Earlier this year, a group of Nova Scotia fishermen failed in their bid to get a court to order Cape Sharp Tidal to suspend its work.

The 175-member Bay of Fundy Inshore Fishermen’s Association argued that the project requires more study to ensure the turbines do not harm marine life. The fishermen wanted the project put on hold until a year-long study could establish a scientific baseline for the state of the bay.

The Nova Scotia government has said the slow-moving turbines are unlikely to have a “food processor effect.”

The turbine, on average, spins at between six and eight revolutions per minute — equivalent to a brisk walking speed if the turbine were to roll along the ground.

Monitoring at the other tidal sites has not recorded a single collision between ocean life and turbines, the government said.

“This is a demonstration project that’s meant to allow the technology to be put in the water and see exactly what interaction it will have with marine life or ecological impact,” Samson said. “The only way for us to do that is to get the turbine in the water.”

The test centre overseeing the tidal generating projects, the Fundy Ocean Research Centre for Energy, has spent over $15 million to date on 110 studies and developed three underwater sensor platforms.

— By Michael MacDonald in Halifax

The Canadian Press

by Canadian Press

Historic first as N.S. tames Fundy’s tides, feeds power to electrical grid

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