This is part of an eight-week series on clean energy.
The relentless tidal currents that rush along coastal regions around the globe could potentially generate huge amounts of power, and big energy companies are scrambling to develop technology to tap them. Giants such as Siemens, Alstom, Électricité de France and GDF Suez are all in the game now, designing tidal turbines or planning large tidal power projects.
At the same time, however, smaller players – including some in Canada – are quietly focusing on more modest tidal hardware, building turbines that can work in shallower water and less powerful currents.
These small tidal turbines won't displace much of the power now generated from big nuclear, hydro, gas or coal plants, but they could contribute to a more distributed electrical grid, and help some isolated communities wean themselves off dirty, expensive diesel generators.
Christopher Gora, president of Clean Current Power Systems Inc., a Vancouver-based turbine maker, acknowledges that the majority of the world's best sites for tidal power are in deep water with powerful currents. But, he insists, there are also many shallower locations that are ideal for smaller installations – and will require far lower capital costs.
The big players, particularly in Europe, want to build large machines for huge projects, Mr. Gora said, because the rewards are potentially large. But the risks are also large. "With smaller sizes, everything is easier and cheaper and faster," he said.
Some of Clean Current's small turbines are designed for ocean tidal settings, but it also has turbines that sit in rivers to generate electricity without the need to build dams or penstocks. Just last month it installed a turbine in the Winnipeg River in Manitoba at the Canadian Hydrokinetic Turbine Testing Centre.
Next year, one of Clean Current's ocean turbines could be in place near Digby, N.S., as part of a project to test the practicality of generating power from the tides in the outer part of the Bay of Fundy.
At Digby, the idea is to focus on establishing modest community-based tidal power systems, using smaller turbines in the tidal flow that runs between the offshore islands, and through Digby Gut – the entrance to the Annapolis River basin.
That's a contrast to the work being done further up the Bay of Fundy, where big multinationals will be testing their turbines in the powerful tidal flow of the Minas Passage, at the Fundy Ocean Research Centre for Energy (FORCE) research site. There, eventually, dozens or hundreds of large underwater turbines could feed a substantial amount of power to the Nova Scotia electrical grid.
At Digby, however, the focus is local. The project is being spearheaded by local investors, through Fundy Tidal Inc., a company funded by people in the region who want to ensure that the electricity – and the benefits of tidal power development – flow to those nearby.
This kind of project "is important for Canada because we have a lot of remote communities all along the coasts that could really benefit from good renewable energy strategies," said Richard Karsten, a mathematics professor at Acadia University who is helping to model the tidal flows in the waters near Digby where the turbines will be placed.
Using local renewable power, combined with "smart grids and smart homes" could be a formidable combination in helping remote parts of the country be more sustainable, Dr. Karsten said.
Indeed, there are hundreds of remote communities across the country that are cut off from the electrical grid, and the majority of them get their power from diesel generators. If those along the oceans could get some of their power from the tides, and the ones on rivers could use small in-stream river turbines, the impact of polluting and expensive fossil fuels could be cut sharply.
The potential market for small turbines in remote communities in Canada alone is as much as $400-million, said Mr. Gora of Clean Current.
But Canada is not alone in targeting this market. More and more global companies are designing small turbines for use in tidal currents.
One of the most advanced is Ocean Renewable Power Co. (ORPC), a Maine-based outfit that makes tidal turbines that look like massive push lawn mowers.
Last year the company successfully installed one of its turbines off the coast of Maine, near the Canadian border at the entrance to the Bay of Fundy. The turbine was connected to the nearby Bangor Hydro Electric Co. system, so it was actually delivering power to the grid.
It has now been removed for evaluation, said John Ferland, ORPC's vice-president of product development, and will be adjusted and redesigned to make it more efficient. An updated unit will be back in the water next year. The "cross flow design" of the turbine, which has a flatter profile than most others, makes it more durable than many other tidal turbines, he said.
ORPC is also planning to test its device at a coastal site in Alaska, Mr. Ferland said, and it has developed a river version of the technology that can also be deployed at remote sites in the north.
Mr. Ferland also hopes to have his company's turbine tested at the Fundy Tidal site in Digby, so it can be considered as a contender on that project. Markets in South America and Asia also beckon, he said.
Europeans companies have also made great strides in the small-turbine field. The Dutch firm Tocardo International BV tested its tidal turbine – which looks like a big propeller – in the waters off the Netherlands this past summer. Tocardo CEO Hans Van Breugel said his company has just opened an office in Halifax to get a toe into the Canadian, U.S and South American market.
While Tocardo will eventually look at large-scale tidal projects, the place to work out the kinks is with smaller turbines, he said. "We see a similarity with wind [power], which also started with smaller turbines," he said. "Near shore is a very interesting starting point."