MIT's Howard Herzog gives his take on the potential of CCS.
Two of the world’s first coal-fired power plants with integrated carbon capture are nearing completion in Saskatchewan and Mississippi, providing a rare lift for a technology that has languished in recent years.
Carbon capture and sequestration (CCS) remains expensive, but the cost of stabilizing the climate could be much higher without it, according to the Intergovernmental Panel on Climate Change (see “The Cost of Limiting Climate Change Could Double without Carbon Capture Technology”). In a report last month, the IPCC noted that CCS is the only way to cut the carbon emissions of existing power plants, and that CCS-equipped power plants burning biomass could help remove carbon dioxide from the atmosphere. The IPCC says both strategies may be essential to limit global warming.
A 110-megawatt plant in Saskatchewan, a refurbished coal-fired generator, is set to restart in a matter of weeks with carbon capture added, according to Robert Watson, CEO for provincial power utility SaskPower.
Under Canadian regulations, the Boundary Dam power station can release no more than 420 tons of carbon dioxide per megawatt-hour of power generation—the same as a state-of-the-art plant fired with natural gas. This is a tall order since the power station will burn lignite—the dirtiest form of coal. Yet SaskPower expects to release just 150 tons of carbon dioxide per day thanks to its new carbon dioxide scrubber, which will absorb and capture 90 percent of the carbon in the plant’s exhaust.
SaskPower could afford to build the $1.2 billion plant partly because lignite is so cheap, but also because Boundary Dam is adjacent to a lignite strip mine. Extra revenue will come from piping most of the 3,000 tons of carbon dioxide that the plant captures per day to Cenovus, a Calgary-based oil and gas firm. Leftover carbon dioxide will be stored in an aquifer 3.5 kilometers below the plant.
“If they couldn’t sell the CO2 for enhanced oil recovery, the project wouldn’t have been economic,” says Howard Herzog, an expert on carbon sequestration, and a senior research engineer with the MIT Energy Initiative.