A massive tidal power turbine, destined for Nova Scotia's Bay of Fundy, location of the world's highest tides. (Photo by Ho New/Reuters).

 

L’ETETE, New Brunswick — For those unaccustomed to the Bay of Fundy’s powerful tides, watching them flow through the mile-wide L’Etete Passage is a disorienting experience.

 

On this rocky, fog-plagued coast, the ocean streaks past like a powerful river, the current so strong it carries small boats backwards and creates whirlpools large enough to swamp them. Six hours later, it flows just as fast in the opposite direction.

 

At the head of the Bay of Fundy 180 miles away, these tides reach 53 feet — the world’s highest — exposing the seafloor for as far as the eye can see at low tide. When the sea returns, the water rushes back in so quickly that you would have to jog to keep ahead of it.

 

People have long dreamed of harnessing these powerful tides to generate power. Franklin D. Roosevelt presided over a massive international energy project that would have dammed L’Etete and the other passages between Passamaquoddy Bay and the Bay of Fundy. The environmental and monetary costs of tidal dams thwarted the project in the early stages of construction, however. Subsequent efforts were also nixed before they got off the drawing board.

 

But now tidal power is back. Supporters hope new technologies will bring clean, renewable energy with little or no harm to the marine environment. These “in-stream” technologies require no dams. Rather, turbines are attached to the seafloor, where they are spun by the tides beneath shipping lanes, unseen and unheard by people ashore.

 

Tidal power has a big advantage over wind energy: the world’s moon-driven tides may be variable, but they are entirely predictable both in terms of timing and force, allowing utilities to know years in advance exactly how much power will be generated at a particular time. But unlike wind turbines, tidal energy technology is still in its infancy, with designs needing further testing before they will be ready to market.

 

“When you’re building a 200-megawatt wind farm you can buy the equipment right off the shelf and you know what you’re getting. Tidal power is not there yet,” says New Brunswick Energy Minister Jack Keir. “We have the highest tides in the world and there’s a wonderful opportunity to take advantage of that, but the technologies aren’t ready for commercial generation.”

 

In mid-October, an Irish company plans to deploy one of the new devices in Nova Scotia’s Minas Basin, at the head of the Bay of Fundy, where the tides are strongest. OpenHydro’s design features a 30-foot wide, 16-fin turbine set in a cowling. The device — which resembles the front of an oversized, but very slowly spinning jet engine — will be tested for two to three years.

 

Two rival designs — from Clean Current of Vancouver and UEK of Annapolis, Md. — will be deployed next year at another government-designated test site, near Parrsboro, N.S. A local company, Minas Basin Pulp and Power, is building the infrastructure to connect the three turbines to the electrical grid. Together they are expected to deliver 3.5 megawatts of electricity, enough to power 4,000 homes.

 

If the turbines withstand winter storms, spring ice floes, and the scrutiny of environmental monitors, it could open the path towards the eventual deployment of 200 to 300 units, together providing ten percent of the coal-dependent province’s electricity generation.

 

“This is a technology that looks promising and that we need to take very seriously if we want to get out of other problematic technologies like nuclear and coal,” says Tim Weis, director of renewable energy policy at the Pembina Institute in Ottawa. “The resource is enormous if they can tap it in a technical, economic, and environmentally acceptable way.”

 

There’s been a flurry of activity in recent years, spurred by the 2007 release of a continent-wide survey of potential tidal energy sites by the Electric Power Research Institute, which found that most of the best sites were in the Bay of Fundy, which is shared by New Brunswick, Nova Scotia, and eastern Maine.

 

In November, an American company, Ocean Renewable Power, will deploy a fourth type of turbine at a site in Eastport, Maine, just a few miles from L’Etete Passage and will charge batteries for the local Coast Guard station. Meanwhile, New Brunswick’s largest private employer, Irving Oil, is in the midst of a $600,000 program to survey 11 potential tidal sites in the province.

 

But not everyone is convinced that tidal power will be a good thing. Mike Dadswell, a professor of biology at Acadia University in Wolfville, N.S., in July wrote to officials that “tidal energy will not be ‘green energy” but rather ‘red energy’ from the blood of its victims.”

 

Mr. Dadswell’s pessimism is informed by his extensive monitoring of fish kills at an old-fashioned dam-based tidal power plant at Annapolis Royal, N.S. There sturgeon, herring and other fish wishing to travel to and from the Annapolis River are forced to swim through a concrete tube and the spinning generator blades mounted inside, which kill by impact and by pressure changes.

 

He says the Minas Basin turbines will also kill many of the fish that attempt to swim through them, with potentially devastating effects on fisheries. “The fish aren’t forced to go through the turbine there, so it all comes down to fish behavior, whether fish approaching these machines will know to turn away,” he says. “It’s literally impossible to turn a blade in the water and not kill, maim, or harm some fish.”

 

John Woods, Minas Basin Pulp & Power’s vice president for energy development, disagrees with Dadswell’s assessment. “If he was talking about the same technology we’re using then there would be some value, but this is quite different,” he says. “We will find out if fish get harmed or not and if they avoid these things…None of us want to see fisheries harmed.”

 

“To answer any of these questions, we have to go out and have this project tested in the real world because we’re not going to get the answers in the conference room,” says Nova Scotia Environment Minister Sterling Belliveau, who was a fisherman for three decades before entering politics. “We are doing this with a very cautious approach and we can shut it down immediately if there are any environmental effects of any kind.”

 

http://www.globalpost.com/passport/foreign-desk/091021/exploiting-the-motion-the-ocean