Wind turbines, solar panels, corn and other bio fuels have been receiving most of the attention from renewable alternative energy advocates. Perhaps soon to move to center stage is an old standby -- hydroelectric power. More specifically, significant advances are currently being made to harness predictable, powerful ocean tides as environmentally friendly energy sources.
France and Canada Take Lead in Harnessing Tides
Harnessing tidal power is not a new concept. Indeed, as an idea it’s been around since the late 19th century, simply waiting for technology to catch up with it. Then, in 1966, an installation at La Rance, France began generating up to 240 megawatts of power. In 1984 at Annapolis Royal, the Nova Scotia Power Corporation began capturing 80-100 megawatt hours daily from the Bay of Fundy tides, the highest in the world. These projects and several similar ones in other parts of the world required construction of large dams, called barrages, to funnel water into turbines when the tides were running.
Very quickly and for good reason, environmentalists pointed out that barrages can cause significant ecological damage, detrimentally impacting fisheries, wetlands, and landforms. For example, while the Annapolis Royal barrage provided an added bonus as a bridge, that didn’t compensate for trapped fish, including at least one humpback whale, and caused river bank erosion on both sides of the structure.
Despite its problems, the barrage method still has its advocates. The British are presently considering construction of a 10-mile long barrage across the Severn River estuary, which eventually could provide as much as 5 percent of Britain’s electricity. If completed, the barrage would be the largest renewable energy project in the world, costing an estimated 20 billion pounds. Moreover, the European Union (EU) has some tough safeguards against environmental degradation which will have to be overcome or satisfied.
Underwater Turbines Provide Solutions
No surprise is it therefore that as criticism rose against barrages, a new method for harnessing the tides is being developed. This method involves placing turbines under the water, anchored to the seabed.
When the method was first proposed, environmentalists expressed concern that the whirling turbine blades would turn fish stock into mulch. Designers soon found a way to solve this potential problem. With that out of the way, more demonstration projects are underway around the world. They can be found in Norway, Northern Ireland, England, Wales, China, South Korea, the United States, and Canada. Other countries seriously considering making a move are Australia, New Zealand, Taiwan, and the Philippines.
In Canada, the success of the 2006 Race Rocks Tidal Power Demonstration Project on Vancouver Island has led to a more ambitious project in the Minas Basin of the Bay of Fundy. The highest tides in the world (up to 54 meters) have been recorded in the Basin. This is another Nova Scotia Power project, partnering with an Irish firm. The first turbine, which will generate one megawatt, will be part of a submerged turbine “farm,” generating power that will eventually be integrated into the province’s main power grid.
Worldwide potential for tidal power is estimated at 3000 gigawatts, although experts concede only about 3 percent of this may be economically exploitable. That, combined with the need to wean industrial countries from their reliance on cheap non-renewable resources for energy production, makes for an uphill struggle as long as costs for renewable energy production remain high. With that, tidal power may still become a significant viable alternative.
