Image: istockphoto.com
In the world wide effort to find sustainable alternatives to fossil fuels, much attention has been focused on the potential of wind power, solar power and biofuels.
While all three have their merits, the dark horse in the race may turn out to be hidden beneath the surface of the ocean. That’s because twice a day, as regular and predictable as clockwork, the world’s water collectively washes one way, and then the other. Harnessing the power of that movement is the dream behind tidal power.
Clean Current, a Canadian-owned company specializing in tidal power technology, is a frontrunner in the race to develop the first viable commercial tidal turbine. Although the task may initially seem simple, the complexity of operating in deep, fast-moving, corrosive salt water has sent countless inventors back to the drawing board. “In salt water,” says Glen Darou, president of Clean Current, “moving parts are vulnerable.” He thinks they’ve solved the problem, however, with a design that has just a single moving part – the turbine blades themselves.
What’s more, the Clean Current design has a relatively high “water to wire” efficiency of 50 percent and it has been designed to have almost zero impact on the underwater environment. Its most recent test site, in fact, was at Race Rocks, a Provincial Ecological Reserve off the south coast of Vancouver Island, where for the first five months of this year it relieved the local lighthouse of its decades-old reliance on dirty diesel power.
What makes tidal power so enticing to investors and environmentalists alike is that water is more than 800 times denser than air, and it can therefore produce significantly more electricity than a typical wind turbine. Clean Current’s 24m diameter model, for example, should be able to produce 5 megawatts in a 7-knot (13km/h) current, enough to power up to 1500 homes. By comparison, a wind turbine would need blades five times that size to produce the same amount of electricity. And unlike wind, tidal power is entirely predictable, even decades into the future. Toss in the fact that two-thirds of the world’s population lives within 400km of the sea and it’s easy to see why dozens of companies around the world are vying to win the race to harness the tides.
Although the stakes are considerable, Darou seems happy to take his time. “This race is a marathon,” he says, “not a sprint. Clean Current has been disciplined in its technology development. Others have skipped steps. Time will tell whether that was wise.”
Having removed their turbine from Race Rocks in May, Clean Current is in the midst of making a few minor modifications to their design. Assuming all goes well, they hope to have their first commercial unit installed by 2009. After that, the ocean’s the limit.
Mark Mallet is a LEED Accredited professional consultant and writer based in Vancouver specializing in the green building industry.
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