• The Chaudiere Falls in Ottawa

    The Chaudiere Falls in Ottawa. (Photo: Shanta: Wikimedia Commons)

WHEN CANADIANS ponder the country’s energy resources, we tend to think about the West and the vast reserves of oil and gas. We often overlook our most abundant energy resource, hydro. Canada, because of its size and geography, is the world’s third largest generator of hydroelectricity, after only China and Brazil. By international standards, Canadians also depend far more on hydro than most of the world does.

In 2007, the Canadian Hydropower Association surveyed its members to determine the full potential of a form of low-carbon energy we tend to take for granted despite the fact that hydro accounts for more than 70 per cent of all renewable power in Canada.

For years, the conventional wisdom among energy experts was that most of the economically viable hydro sources in Canada had been harnessed. While almost two-thirds of Canadian electricity comes from hydro generating stations, the system’s total capacity has grown very modestly in recent years — a far cry from the 1950s, ’60s and ’70s, when Herculean dam projects in Quebec, Ontario, Manitoba and British Columbia flooded vast areas, displaced hundreds of aboriginal communities and funnelled power to the fastgrowing cities thousands of kilometres to the south. Today, hydroelectric facilities generate almost all the power used in British Columbia, Manitoba, Quebec, Newfoundland and Labrador, and the Yukon. Elsewhere, hydro stations co-exist with coal, natural gas and nuclear. Hydro’s overall share of Canada’s electricity mix has ebbed with the growth of wind, solar and biomass production in regions far closer to population centres.

The results of the association’s survey showed for the first time the full theoretical extent of the resource: the group’s consultants estimated that Canada has about 160,000 megawatts of untapped hydro power — more than twice the country’s current capacity, or the equivalent of 80 Niagara Falls. But as of 2014- 2015, only about 8,300 megawatts of hydro power capacity was either being built or under consideration, according to the federal government.

Of course, not everyone agrees that Canada should be gearing up for a new era of hydro ventures. Some environmental groups worry that hydro facilities will inflict irreversible ecological damage to ecosystems already stressed by the symptoms of climate change. “The premise that big hydro has to be part of the solution has a bunch of flaws,” says Jay Ritchlin, acting director of science policy for the David Suzuki Foundation in Vancouver. “The demand side has not been properly addressed.”

Still, the possibility exists that these very remote resources could not only be brought to market but also play a role in altering North America’s carbon performance. In recent years, Quebec and California have established a cap-and-trade market, and Ontario is poised to join. British Columbia and Alberta now levy carbon taxes, and Alberta, under Rachel Notley’s NDP government, is moving to phase out coal. The Paris climate accord further commits Canada and the United States to accelerated emissions reductions, and the federal government is promising a suite of new climate change policies.

If Canada and the United States begin to impose stiffer carbon pricing policies and accelerate the shift away from coalfired generation, Irving says the daunting economics of large-scale remote hydro development may begin to change. Such a shift, moreover, reflects the general trajectory of hydro development around the world. According to the Canadian Hydropower Association, global capacity has grown 27 per cent in the past decade alone, with significant investments in the developing world.

It remains to be seen if these trends will spark a renaissance in Canadian hydro power or if the economical and ecological challenges of building new facilities are too great.

POWER STORING

IN RECENT YEARS, with the rapid growth of intermittent energy sources such as wind and solar, utilities and power system operators have begun figuring out how to combine these sources with hydro as a means of storing energy. Power from wind and solar can be “stored” by using the electricity generated to drive pumps that fill elevated reservoirs. When demand rises, the stored water can be released through turbines that generate electricity. One of the problems with this idea, however, is that small-scale pumped hydro storage systems tend not to be very economical.

Drawing on a technology patented by a Japanese inventor, Cameron Lewis and Curtis VanWalleghem, co-founders of a five-year-old company called Hydrostor, developed a system that stores compressed air in heavy-duty balloons suspended at the bottom of a water body (above). The hydrostatic pressure from the water keeps the air compressed. When needed, it can be released to drive a generator.

Last fall, Hydrostor and Toronto Hydro launched a 660-kilowatt pilot project from a small facility on Toronto Island, with financing provided by both the federal and provincial governments.

Such systems, VanWalleghem says, can effectively serve as batteries that store wind or solar energy by using the electricity to drive the air compressors. He says the system is about 60 per cent efficient, meaning that the electricity used to drive the pumps consumes a portion of the energy produced by wind or solar installations. (Heat from the pump can be recovered to boost efficiency to 80 per cent.)

VanWalleghem believes the technology is scalable and can be deployed in any town or city located on a large water body. “It’s absolutely practical to do 100 megawatts,” he claims, but adds that the earliest applications will be in remote communities — either up North or on islands — that rely on diesel generators for their power.