On October 2, the Boundary Dam power plant in Saskatchewan became the first full-sized coal-fired boiler to capture the copious carbon dioxide that had previously billowed from its smokestack, preventing the greenhouse gas from entering the atmosphere. On the resulting invisible stream of hot smoke ride the hopes of combating climate change while still burning fossil fuels.

Such CO2 capture and storage (CCS) "is the only known technology that will enable us to continue to use fossil fuels and also de-carbonize the energy sector," said Maria van der Hoeven, executive director of the International Energy Agency, in a statement on the opening of the Boundary Dam plant. "As fossil fuel consumption is expected to continue for decades, deployment of CCS is essential."

That deployment is beginning to happen in fits and starts, and with lots of government support. For example, the Mississippi-based Kemper Facility, a power plant that will turn brown coal to gas and strip off the CO2 in the process, is due online in 2015—a year behind schedule and at a of cost $5.6 billion, more than twice its initial estimate. And the U.S. Environmental Protection Agency has approved plans by Archer Daniels Midland (ADM) to inject CO2 captured at its ethanol fermentation facility in Illinois into a saltwater aquifer deep underground.

Boundary Dam also burns brown coal, the most polluting form of the most polluting fossil fuel. Saskatchewan has an estimated 300-year supply of the dirty fuel to burn at present rates of consumption. The unit uses amines—a nitrogen-based molecule that can bond with CO2—to capture a projected 1 million metric tons of the leading greenhouse gas each year. The amine captures the CO2 and then when further heated releases it again, meaning it takes away some of the plant's power to take away the plant's CO2. The captured CO2, compressed and liquefied, will then travel 66 kilometers via pipeline to the nearby Weyburn oil fields and join the CO2 captured at a plant that turns brown coal into a gas in North Dakota. At Weyburn, the CO2 will be used to scour more oil out of the ground. Of course, the eventual burning of this oil will also release CO2 into the atmosphere.

But such "enhanced oil recovery" is the only way to make capturing CO2 affordable, other than outright government subsidies, which Boundary Dam also benefited from. The province of Saskatchewan is the primary owner of the power company—SaskPower—that owns and operates the plant and the Canadian federal government kicked in C$240 million for its construction. Boundary Dam’s five coal burners churn out 730 megawatts worth of power; one of them—Unit 3—will now capture 90 percent of the CO2 it would otherwise spew into the atmosphere while the other four will continue to spew CO2 unabated. The total cost of the retrofit of that one boiler in Unit 3 was C$1.35 billion. SaskPower hopes to raise rates by more than 15 percent in order to pay for it. Such CO2 capture technology adds at least $0.04 per kilowatt-hour to the cost of electricity, according to the U.S. government.

For the first time, however, any excess CO2 that is not purchased for use in the oil field will not just be dumped in the atmosphere at Boundary Dam. Instead that excess CO2 will be stored in a saltwater aquifer, as part of the ongoing research project known as Aquistore. Such storage, which is intended to be permanent, is the key to making so-called clean coal actually work to combat climate change. As it stands, the ADM project in Illinois is the only facility on track to achieve that goal and it ferments ethanol. The U.S. has an estimated storage capacity of 4 trillion metric tons, more than enough to store pollution for decades if power plants begin to capture CO2.

With Boundary Dam, there are now 13 such capture and storage projects up and running around the world, most of which involve storing the CO2 that comes mixed with certain natural gas deposits. Ten of the 13 projects are in the U.S., where they garner a tax credit of at least $10 per metric ton captured. The IEA estimates that at least 100 such facilities are needed just for coal-fired power plants by 2020 to capture and eliminate permanently 270 million metric tons of CO2 annually in order to keep global warming below 2 degrees Celsius.

And that number is certainly optimistic. All told the current 13 projects capture roughly 20 million metric tons of CO2 annually—almost none of it from burning coal—compared to at least 15 billion metric tons of CO2 pollution from coal-fired power plants globally. The U.S. alone burns more than 700 million metric tons of coal a year, which contributes roughly one-third of its overall CO2 pollution, and has devoted more than $9 billion to CCS research and development just since 2009 without a single CCS project at a full-scale power plant. And coal use globally is projected to double by 2020, largely due to growth in burning the dirty rock in China and India. There are more than 1,000 coal-fired power plants planned or being built around the world, and only a handful include the technology to capture CO2 pollution, let alone remedies for the other pollution problems that plague coal: acid rain, smog, toxic ash.

Furthermore, not all CO2 capture and storage projects that start, continue either. The Mountaineer Power Plant in West Virginia had a chilled ammonia chemistry set that captured CO2, but due to a lack of subsidies and other support the project was discontinued in 2011. The equipment to capture CO2 still sits, unused, on the power plant grounds, slowly rusting.