Clean-coal technology is proving costly, will take decades to become commercially viable, and will not adequately resolve coal's polluting footprint, they add.
"Clean coal doesn't exist - it's a PR device," says Jack Gibbons, chair of the Ontario Clean Air Alliance, a non-profit that helped convince the government in that province to decide to phase out its coal-burning power plants, of which four currently remain, by the end of 2014.
The "clean" in "clean coal" refers to a reduction of its environmental impact when burned to generate electricity. Three main technologies - pre-combustion (gasification), post- combustion and oxygen-fuel combustion - have come to the fore, designed to isolate pollutants so they can be sequestered underground or otherwise stored and not sent up the stack.
For now, coal remains a big deal in electricity generation.
According to the Calgary-based Coal Association of Canada (CAC), coal generates roughly 39 percent of the world's electricity and 17 percent of that used in Canada.
With mines in British Columbia, Saskatchewan and Alberta, and to a lesser extent in the Maritimes, Canada ranks 10th globally in total reserves, with four billion tonnes of bituminous coal, the kind burned to generate power.
The CAC and other advocates say Canadian coal offers more stored energy than do all of our oil, natural gas and oilsands supplies combined.
"To satisfy Canada's energy demands going forward, you need to keep all sources of energy on the table," says Bob Stobbs, executive director with the Canadian Clean Power Coalition, an industry group whose members predominantly include coal-burning utilities from Alberta, Saskatchewan, Nova Scotia and North Dakota.
"We're going to need everything we can get our hands on."
Stobbs notes natural gas has experienced wild price fluctuations and other energy options also bear a high price tag.
However, coal's carbon-rich quality is also its Achilles heel. With an age-old reputation as sooty and polluting, coal is under fire from scientists who say its burning accounts for a significant percentage of global greenhouse gas emissions.
George Nutter, a spokesman for the Ontario Ministry of Energy and Infrastructure, says the decision to move away from coal is based on environmental and economic reasoning.
"The government is interested in reducing carbon-dioxide emissions, and there's no technology in place commercially at this point in time that addresses this," he says.
The province sees natural gas, nuclear power and renewables as part of an overall energy mix, he adds. "We looked at the most cost-effective approach and determined that meeting Ontario's electricity needs did not require coal-fired plants."
However, clean coal still has widespread political support, particularly in the United States. When they stumped through Appalachia - the heart of U.S. coal country that stretches from southern New York state to northern Alabama, Mississippi and Georgia - during the recent U.S. presidential campaign, both John McCain and Barack Obama supported clean coal.
Obama, slated to be sworn in January 20, outlined spending on clean coal and other technologies in order to reduce greenhouse-gas emissions.
In Canada, successive governments have also backed clean coal.
Bill Pearson, a research engineer with Natural Resources Canada, was a project leader when the then-Liberal federal government launched its Clean Coal Technology Roadmap in 2002 to see how coal might gain a new, clean lease on life.
"Coal was looked at as a fuel that emitted a lot of pollution, and there was pressure to bring it to near-zero emission," Pearson says.
"There's particulates, nitrogen oxide, sulphur dioxide and mercury, but what really tipped the scale was carbon dioxide," he adds. "Its emission intensity relative to other fossil fuels is very high. Something had to be done, and it wasn't just a matter of tweaking. We looked at major design changes and we're trying to have coal-fired power plants be near zero emissions by 2020."
Gibbons of the Ontario Clean Air Alliance says existing clean-coal technologies may reduce nitrogen oxide, sulphur dioxide and other particulate emissions, but do not resolve problems with carbon dioxide because plants have to burn more fuel to produce each kilowatt-hour of electricity, thus increasing their net greenhouse-gas emissions.
He adds that clean-coal technology has large capital costs and is a decade or more from commercial availability.
"There are much better ways to invest taxpayers' money than trying to make coal clean," he says.
"The coal industry wants taxpayers to subsidize their research and development programs, to help their industry survive, but you get a much bigger bang for your buck by investing in energy efficiency, renewable energy and natural gas-fired combined heat and power technologies."
In February 2008, the federal government announced that its budget included $240 million toward a $1.4-billion carbon-capture project planned in Saskatchewan and the Alberta government is in the process of funding a $2-billion program.
"We're looking at technologies that capture 80 to 90 percent of CO2," says the Canadian Clean Power Coalition's Stobbs. A couple of small-scale pilot projects are underway in the U.S., he adds, but widespread deployment is about a decade away.
In the U.S., clean coal has come under fire from critics who say it doesn't account for mining, which has its own set of environmental and social consequences.
One particularly controversial form of mining, mountain-top removal, occurs deep in the heart of Appalachia.
In some areas, residents have organized against mountain-top removal, saying effects include air pollution from contaminants such as ammonium nitrate and silica, as well as flooding and other damage to homes, private property and wildlife habitat.
Although mountain-top removal is not practised in Canada, Appalachia does export coal to Canada. Ontario Power Generation spokesman Ted Gruetzner confirmed the utility burns coal from Appalachia and from elsewhere in the U.S., but he would not specify exactly where that coal comes from, or how it is mined.
Recently, a group of reporters from the Society of Environmental Journalists' annual conference travelled to West Virginia to learn more about the mining controversy in that state.
Julia Bonds, who lives in rural West Virginia, says entire mountain tops are blasted with dynamite to access foot-thick seams deep underneath. Trees are often burned rather than harvested, excavated soil and rock is dumped in valleys, creeks and streams are polluted, and communities where coal is mined face increased health problems and don't see wealth from the resource trickling down, she says.
"The poorest communities in Appalachia are the ones that extract and process the coal," says Bonds, an environmental activist and executive director of Coal River Mountain Watch. "Instead of independence from foreign oil, we need independence from fossil fuels."
Andrew Jordan, president and owner of Pritchard Mining in West Virginia, says he grew up in nearby Charleston, cares about the environment, and has worked hard to ensure his company rebuilds mountain areas to match their old contours and reforests with native oak, pine, sugar maple and white ash.
"We won an award from (U.S.) Department of the Interior for reclamation. When we're finished, it's in better shape environmentally than when we started," he says.
In Canada, CAC president Allen Wright says roughly 95 percent of the coal mined here comes from surface mines, and land is reclaimed.
"Teck Coal (formerly Fording and Elk Valley Coal) has been mining in southeastern British Columbia and reclaiming land for 40 years," Wright says, adding that similar efforts at the Gregg River coal mine in Alberta have benefited elk, grizzly bears and birds. "The wildlife population there is healthier now than it's ever been."
Still, Kevin Stewart, a campaigner with the Western Canada Wilderness Committee, expresses skepticism.
He has been working to keep the Dodds-Roundhill mine and gasification project from opening about 80 kilometres southeast of Edmonton, saying coal mining would require water to be pumped from a nearby lake, which would disrupt the area's watershed and adversely affect wetlands that are considered an important habitat for migrating birds.
"The landscape has been in place since the glaciers retreated 10,000 years ago," Stewart says, adding he cannot believe man-made land reclamation efforts can match what nature has achieved through evolution.