Tides seen as energy source
Never-ending surges could deliver more reliable form of renewable power generation
ABOARD THE PLAT-I 6.40 GENERATING PLATFORM, Nova Scotia — The Bay of Fundy, off the Canadian provinces of Nova Scotia and New Brunswick, has long tantalized and frustrated engineers hoping to harness its record-setting 50-foot-high tide to generate electricity.
After more than a century of attempts, there has only been one small power-generating station, since closed, and countless broken dreams, abandoned plans and bankruptcies.
Even so, a new coalition of entrepreneurs and scientists in Nova Scotia are trying again. One participant, a company called Sustainable Marine, has devised a new technology and successfully operated it for more than seven months, longer than any other similar system, producing enough electricity for about 250 homes.
Sustainable Marine’s innovation is that rather than placing stationary turbines onto the seabed as has been tried in the past, it floats movable ones on the surface, lifting them when a dangerous object approaches and for maintenance.
If the platform continues to prove reliable, is economically viable and doesn’t harm marine life, it will have harnessed not just a new source of renewable energy, but also one of the most reliable ones in the world. Because unlike wind or sunshine, tides are unceasing and completely predictable.
Sustainable Marine is one of five racing to produce a viable method of electrical generation in the Bay of Fundy and, it hopes, in dozens of similar tidal regions in the world.
Scientists collaborating with a government-financed research center are studying the impact of the technologies on marine life. A fishing group unsuccessfully went to court six years ago to block the deployment of a turbine at the center’s test site.
Regulators required Sustainable Marine to outfit its platform with a variety of underwater sensors and cameras to track sea life and to automatically lift the turbines when whales or other large creatures approach.
If Sustainable Marine’s underwater sensors and cameras confirm assertions by the tidal power generation industry that fish, whales and other sea creatures will safely swim around their turbine blades and the prototype proves reliable, it may become part of a large-scale development.
Engineers and scientists in Nova Scotia are driven to harness the tides partly because the province is one of the few in Canada that still relies heavily on fossil fuels to generate power.
While the country’s three largest provinces long ago traded fossil fuels for other energy sources, Nova Scotia still produces 51% of its electricity by burning coal.
Every six hours in the Minas Passage — the narrow portion of the bay near the port of Parrsboro, Nova Scotia — the water level rises or falls about 55 feet.
In all, 14 billion metric tons of water make the trip across the bay every 12 hours at speeds of up 12 mph. The Minas Passage is estimated to have the potential to generate about 7,000 megawatts of power, more than double the amount of electricity currently generated by other sources for the province of nearly 1 million residents.
The Bay of Fundy’s funnel shape is part of the reason for its exceptional tides. Along its 96 or so miles of length, the bay dramatically narrows and its depth drops from 765 feet to 147 feet.