Technology

Cleaner and greener

Coal suffers from a bad reputation. But new technologies developed in Canada may change that.

Out of the mist, a group of workers heads into a coal mine. But this isn't any ordinary group of miners–the men and women are picture-perfect, their chiselled bodies glistening with sweat as they proceed to their swing tools. At the end of what turns out to be a television commercial for U.S. conglomerate General Electric, a voice-over proclaims: “Harnessing the power of coal is looking more beautiful every day.”

OK, so maybe it's a bit of a stretch for GE, advertising its role in developing environmentally friendly sources of power, to try to make coal mining look sexy–and the commercial generated a fair bit of controversy when it was released in 2005. There's really no getting around the fact that in this day and age of increasing worries about the environment, coal, for many, is a four-letter word. The United Nation's Intergovernmental Panel on Climate Change raised the level of public concern when it released a report on Feb. 2 concluding scientific evidence shows “warming of the climate system is unequivocal,” and it is “very likely” that human activity–including the burning of fossil fuels such as coal, which produces carbon dioxide, a greenhouse gas–is the main contributor to rising temperatures over the past 50 years.

As concerns about global warming rise–and the role that current methods for generating power plays in the heating up of the planet–new ways of using coal in a more environmentally friendly fashion are beginning to get a closer look. The fact that both Canada's governing Conservative party and the Liberal Opposition are embracing research and investment into so-called clean coal technology is one sign that the tide of public opinion against coal–long written off as a 19th-century technology–may be gradually shifting. In January, federal Environment Minister John Baird and Natural Resources Minister Gary Lunn announced a $230-million investment in environmentally cleaner technologies, including clean coal research. New federal Liberal leader and former Environment Minister Stéphane Dion, known for his commitment to green issues, also believes clean coal technology has the potential to meet Canada's energy needs and limit our greenhouse emissions. “I think there are cleaner coal possibilities,” Dion told a Bay Street crowd in January.

Tom Adams, executive director of Energy Probe, a consumer and environment-oriented watchdog based in Toronto, is a major advocate of clean coal technologies. He says it's high time politicians started to address both the growing demand for energy and public concern about global warming. Sure, it's important to encourage energy conservation and efficiency, as well as develop renewable wind, solar and hydro energy. But coal, for all its current faults, Adams insists, can't be easily replaced by nuclear energy or natural gas.

It's a lesson Ontario Premier Dalton McGuinty learned the hard way when he had to admit last November that he couldn't keep an election promise to close all of the province's coal plants by 2007. The earliest date McGuinty now gives for the last coal plant shutdown is 2014. Adams says that wind, sun, hydro and nuclear options either don't provide a reliable power supply, or can't be easily turned on or off based on demand. Only natural-gas-fired power plants have the same flexible characteristics as coal for meeting peak and base load demand, he says. But natural gas prices are volatile, and generally headed upward, so Adams says it's not a power source we want to rely on. The answer is cost-effective, environmentally friendly, power from coal.

Canada has vast coal deposits (mainly out west) that could provide hundreds of years of energy. And realistically, with coal currently generating a quarter of Canada's power–between 60% and 70% in Alberta, Saskatchwan and Nova Scotia–Adams says the resource is not going away anytime soon.

The confusion surrounding “clean coal” partly stems from the fact that the term is used interchangeably to describe methods that are cutting edge and those that simply involve “cleaner” coal. Coal power has come a long way in removing or reducing harmful pollutants, like mercury, sulphur dioxide and nitrogen oxide, thanks to better filters, scrubbers and burners. But it takes more than that to conquer greenhouse-gas carbon dioxide emissions.

The traditional method for producing electricity from coal is to burn pulverized coal to heat water for steam. This generates electricity, but also creates carbon dioxide. No techniques exist for burning coal without creating carbon dioxide; the best we can do is capture it and store the gas. There are three clean coal technologies available for separating out carbon dioxide to make it available for capture: the so-called integrated gasification combined cycle method, which turns coal into a synthetic gas (syngas) that can be used either as a fuel to generate electricity or for a variety of other purposes; post-combustion removal of carbon dioxide using scrubbers; and what is known as the oxyfuel method, which removes nitrogen at the beginning of the coal-burning process. The last method captures a higher percentage of the CO¸ than the other two–95% or more compared with just over 90%.

The solution to finding both a clean method for generating coal, then storing the carbon dioxide, could come out of important, world-class research now being headed by Malcolm Wilson, director of CO¸ management with the Energy Innovation Network, a research group sponsored by various government, corporate and university bodies, including the University of Regina, where Wilson is based. He says the technologies needed to develop clean coal power are readily available; it's a matter of combining them in a commercially viable way at a cost that society is willing to accept. Much of the work of Wilson and others at the university–home to the International Test Centre for CO¸ Capture, one of only four major research centres in the world devoted to developing such technologies–centres on a pilot project at Boundary Dam Power Station, near Estevan, about a two-hour drive southeast of Regina. There, they are looking for cost-effective ways for generating electricity with clean coal methods, including the capture of carbon dioxide.

The Boundary Dam project uses the post-combustion process. It is slightly less effective than the oxyfuel method for separating CO¸, but one (continued on page 49) (continued from page 46) advantage it does have is that it can be added on to existing coal-fired plants currently using traditional “dirty” technology. Oxyfuel and coal gasification technology can only be considered if building a new plant is an option.

Wilson says the Boundary Dam project captures about four tonnes of carbon dioxide each day–admittedly only a tiny percentage of the 6,000 tonnes of greenhouse gas emitted daily by the power plant. However, he adds that the initiative has shown good results in reducing the cost of clean coal power while capturing carbon dioxide. Right now, Wilson says the cost of producing clean coal electricity with post-combustion methods is about 40% to 50% higher than conventional methods. “What we need now is the next step,” Wilson says, noting the technology needs testing on a far larger scale.

According to Wilson, research that has already been done indicates that with the right geological conditions, carbon dioxide can be safely stored underground. Used oilfields in Western Canada are ideal for this purpose, he notes, since fossil fuels had been trapped underground there for millions of years. But on top of that, putting captured carbon dioxide to some commercial use would go a long way to making clean coal economically viable.

So far, the best commercial use for large amounts of captured carbon dioxide is to inject the gas into existing oil-well fields to help increase the amount of oil that can be taken out of the ground. The carbon dioxide, when liquefied and pumped into oil-rich rock, acts as a kind of solvent, helping to free up oil so more can be taken out of the ground in comparison to traditional drilling methods alone.

The injection of carbon dioxide into the ground, which might one day increase oil production at existing wells, is the focus of research now being done by the Weyburn-Midale CO¸ Monitoring and Storage Project in Saskatchewan. It is funded through various government agencies, international bodies and oil producers, including EnCana, and is being co-ordinated by the Petroleum Technology Research Centre (PTRC) located at the University of Regina, which is also a sponsor. Since 2000, as part of the research, carbon dioxide that otherwise would have ended up in the atmosphere has been injected into porous rock under farmers' fields south of Weyburn, about 100 kilometres southeast of Regina. About 5,000 tonnes a day is stored at the Weyburn site; about 1,400 tonnes a day at the nearby Midale site.

Ray Knudsen, PTRC's director for the project, says injecting carbon dioxide into the Weyburn well, in production since the 1950s, has resulted in an incremental daily output of 18,000 barrels, with total daily production now close to 30,000 barrels. The venture is also cost-effective, he says, with enhanced production offsetting the cost of carbon dioxide capture.

The carbon dioxide used at Weyburn is piped in 320 kilometres from the Dakota Gasification Co. plant in Beulah, N.D. Since the start of the Weyburn-Midale project, over seven million tonnes of carbon dioxide that otherwise would have spewed into the atmosphere has been diverted underground to help boost oil production. As for the syngas produced at the Beulah plant, it's burned to generate electricity.

But using syngas to create power is just one potential use for coal gasification technology. Energy Probe's Adams points to a recently proposed project in Alberta that could have “huge implications” for cutting greenhouse-gas emissions coming from the province's oilsands. In January, Sherritt International Corp.–a publicly traded coal miner based in Toronto–filed a public disclosure document saying that it intends to build Canada's first coal-gasification plant on a site about 80 kilometres southeast of Edmonton. What's interesting about the Dodds-Roundhill Coal Gasification Project, says Adams, is that it would process coal into syngas, which could then be turned into high-purity hydrogen. Hydrogen is required to process crude oil in Alberta's booming oilsands industry. Carbon dioxide would be a byproduct of this process. Currently, the oilsands draw the hydrogen they need from natural gas, so the use of syngas to create hydrogen would preserve natural gas reserves for domestic consumption or export.

Adams acknowledges the Sherritt proposal is an “interim” step in developing clean coal technology; its hydrogen output would be used for creating another fossil fuel and is not an end source of clean power. But it's an important step, he says, since the plant would have the capacity to capture up to 12,000 tonnes of carbon dioxide each day. And, with an estimated 33.6 billion tonnes of coal in Alberta, about 70% of Canada's total known coal reserves, it's a huge source of untapped energy potential.

Still, the ultimate goal for those who are looking at ways of unleashing the power of coal in its cleanest form, is the construction of a commercial-scale “zero-emissions” power plant. Again, it is Saskatchewan that could lead the way in coming up with a solution. By this summer, SaskPower, the Crown corporation responsible for the province's power needs, will make a decision on whether it will build a $1.5-billion power station that will use the oxyfuel process for generating electricity. The project would also capture and store carbon dioxide. The site has already been chosen–it's next to the existing Shand Power Plant, which, like the Boundary Dam, is close to Estevan. SaskPower chose oxyfuel over post-combustion and gasification methods mainly for its potential to capture the most carbon dioxide.

If built by its projected completion date of 2011, SaskPower's oxyfuel power plant could produce up to 300 megawatts of electricity and capture 8,000 tonnes of carbon dioxide daily. It would be the first plant of its kind on such a large scale. Max Ball, the manager of SaskPower's clean coal project, admits that the oxyfuel option would have to compete with traditional methods for increasing the province's power supply, including conventional coal-generation technology and importing electricity. While Ball says he is confident the numbers will show that oxyfuel can compete with the other options, if it is found to be the more expensive, it will provide a “real test” of public will to support greener ways of generating power. “Notionally, society says it is prepared to pay more,” he says. “What nobody knows is how much society is prepared to pay.”

So far, the SaskPower oxyfuel plant is just a dream. But the fact that Canada is getting very close to developing commercial examples of world-class clean coal technology is impressive. And, as the GE “sexy coal” ad points out, maybe it's time we acknowledge that the potential of clean coal is looking pretty good.

worries about global warming are driving innovative

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