HALIFAX—Every six hours, 160 billion tonnes of seawater flows into—or out of—the Bay of Fundy. That’s more than four times the flow of the Amazon, the Nile and every other freshwater river in the world… combined.
In some places, the tide will rise over 16 meters. When it recedes, it can expose the ocean floor for as much as five kilometers out.
Those tides — the largest in the world — have made the bay a draw for tourists around the world, who flock there in hordes to walk a newly exposed ocean bottom, or to kayak on its rising waters.
But in the eyes of some, it’s also a vast, untapped source of potential green energy, one that no one has yet been able to fully harness.
That may change soon as, for the first time, a company — using a 30-metre-long and 30-meter-wide floating turbine platform — has successfully managed to convert the power of the world’s largest tides into electricity for Nova Scotia’s power grid .
And that could open the door to a predictable, renewable energy supply on any stretch of coastline with a significant tide — an eye-watering prospect for a country that sports oceans on three sides.
Edinburgh, Scotland-based Sustainable Marine announced this week that its floating tidal turbine platform PLAT-I 6.40 had connected to the Nova Scotia grid from its site at Grand Passage, near the southern tip of Digby Neck in the southwest of the province.
At peak flow, it’s capable of pumping out 420 kilowatts. That’s enough to power 420 houses, more than adequate for the entire population of nearby Brier Island.
“This is the first time that energy from a system like ours is actually dropping onto a grid and getting used by people and helping to kick Nova Scotia’s coal habit,” said Sustainable Marine CEO Jason Hayman.
“The Bay of Fundy is just an amazing tidal energy resource. It’s a massive, massive resource, but it hasn’t been technically feasible or practical up to now to use it.”
Nova Scotia Premier Tim Houston acknowledged the accomplishment as “a first in Canadian tidal energy history.”
“This project and others are positioning Nova Scotia as a global player in the tidal energy sector and are creating green technologies, green jobs, a cleaner environment and a predictable, renewable source of electricity for Nova Scotians,” he said in a release shortly after the platform first delivered power to the provincial grid.
Fundy’s tides could, if efficiently harnessed, go a long way toward the province lessening its dependence on coal-fired power plants and meeting its professed goal of having 80 per cent of Nova Scotia’s electricity needs supplied by renewable energy by 2030.
That’s a tall order. Nova Scotia’s four coal power plants supply 1252 mW to the province, by far the largest portion of its generating stations.
There’s a huge gap between the 420 kW maximum output of one of Sustainable Marine’s platforms, and, for example, the 620 mW output of the province’s largest coal power plant. But one of the highlights of the Sustainable Marine design is that the platforms are modular and scalable.
Each catamaran-shaped platform boasts six turbines, each looking a little like a powerboat’s outboard motor. Like an outboard motor, the turbines can each be tilted out of the water for maintenance. A turret on the platform allows it to orient itself with the flow of the tide. Each platform can be linked to another to increase the amount of electricity generated.
The Grand Passage platform is a proof-of-concept trial, said Hayman. When those tests are completed, that platform will travel north to link up with two more platforms in the Minas Passage at the Fundy Ocean Research Center for Energy (FORCE). Together, while environmental monitoring goes on, they should be able to generate 1.26 megawatts from the tides.
But that’s just the tip of the iceberg, said Hayman. He said he anticipates that in the future floating turbines could be pulling hundreds of megawatts of electricity out of the Bay of Fundy.
In the Minas Passage alone, he said, the province could easily place 100 of the platforms without coming close to blocking the strait.
“The room is there, and the resources are there to do hundreds of megawatts and actually have a real meaningful impact,” he said.
At the other end of the scale, smaller groupings, or even individual platforms could generate electricity in coastal waters anywhere that has a tide flow of about five knots. And that means it could potentially serve smaller coastal communities — some of which may still rely on diesel generators for electricity.
In British Columbia, for example, the platforms could generate power for communities along the passage between Vancouver Island and the mainland, and further north along the coast, for communities along the Inside Passage between Port Hardy and Prince Rupert.
But before any of that happens, the platforms will face a battery of tests at FORCE. Along with assessing their viability as a renewable energy alternative, FORCE will be studying the potential effects of their turbines on marine life, marine noise and other environmental variables.
Hayman acknowledged that if the Sustainable Marine platform is going to attain widespread usage, there will have to be a level of acceptance from those living in and around the Bay of Fundy.
“This is new technology and people need to get comfortable with it. If you’re going to put stuff in the community’s backyard, they need to feel comfortable that it’s safe, that there’s not going to have any adverse impacts on wildlife or on their livelihood.”
If some skepticism exists, it is not without reason; to extract electricity from the tide efforts haven’t come without failures, some of which still remain at the bottom of the ocean.
In 2009, a prototype turbine that sat on the ocean floor in the Minas Passage was torn apart by Fundy’s fast-moving tides, which can exceed 10 knots or 18 kilometers an hour.
And in July of 2018, Cape Sharp Tidal connected an ocean-floor mounted, two mW tidal turbine to the grid. But that venture was short-lived, ending when one of its owners, Dublin-based OpenHydro declared bankruptcy the very next day.
The turbine, which was damaged beyond repair only a couple of months after it had been deployed in the Minas Passage, is still sitting on the ocean floor.
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