First Look at Carbon Capture and Storage in a West Virginia Coal-Fired Power Plant [Slide Show]
The world's first power facility to capture and store a portion of its carbon dioxide has begun operating in Appalachia
![First Look at Carbon Capture and Storage in a West Virginia Coal-Fired Power Plant [Slide Show]](https://static.scientificamerican.com/sciam/cache/file/B4222C44-617C-433C-9B2EC9F6A98A1C77.jpg?w=590&h=393)
First Look at Carbon Capture and Storage in a West Virginia Coal-Fired Power Plant [Slide Show]
- CLEANER COAL?: Capturing CO2 from all that coal burning is vital to any efforts to combat climate change, according to the U.N. Intergovernmental Panel on Climate Change and other experts. The unit at Mountaineer is one of at least 14 projects around the world aiming to make carbon capture and storage technologically and economically viable. © David Biello
- COAL POWER: The U.S. and China together burn more than four billion metric tons of coal annually, and Mountaineer consumes 3.5 million metric tons in a typical year—10 to 12 barge loads a day—some of which is transported by train from as far away as the Powder River Basin in Wyoming. Mountaineer even has a coal mine of its own directly attached to the power plant via a conveyor belt, although the local source supplies enough coal for just one day's worth of power a week, says J. L. Perry, the plant's energy production superintendent. © David Biello
- CLEAN COAL?: The carbon-capture-and-storage unit at Mountaineer eliminates roughly 1.5 percent of the carbon dioxide the plant would otherwise emit. And other issues remain, such as the ash visible in the storage ponds for the Philip Sporn Power Plant in the background. Old power plants like that one have no pollution controls; the only visible sign of the plant's emissions of smog-forming nitrogen oxides and acid rain-causing sulfur dioxide—along with tons of CO2—is an occasional faint haze. Courtesy of Alstom
- SMALL DEMO: A prior demonstration with a smaller unit at the Pleasant Prairie power plant in Wisconsin proved that the chilled-ammonia technology could capture more than 90 percent of the CO2 from just under two megawatts' worth of flue gas. That CO2 was then vented back up the smokestack because Wisconsin lacks the geologic formations to enable storage. Courtesy of We Energies
- DEEP STORAGE: The captured CO2 is stored more than two and a half kilometers underground in the pores between the grains of rock that make up sandstone, which is usually filled with brine. Intervening layers of shale and limestone should also keep the CO2 from leaking back to the surface. Courtesy of AEP / Battelle
- REGENERATION: The ammonium bicarbonate is pumped to these tall, thin reaction towers where steam is added to raise the temperature and pressure. That increase drives its transformation back to pure CO2, which is separated out. The original ammonium carbonate is recycled to go through the process again. © David Biello
- CARBON CAPTURE: The cooled flue gas enters the central, wide column (pictured here) at Mountaineer. Inside the tall tank, a slurry of ammonium carbonate—better known as baker's ammonia—pulls 90 percent or more of the CO2 out of the flue gas by chemically reacting to form ammonium bicarbonate. © David Biello
- COLD CAPTURE: Flue gas from coal burning is cooled from roughly 150 degrees Celsius out of the boiler to 55 degrees C after going through various cleaning processes. It is further cooled to less than 20 degrees C before entering the carbon-capture unit—as laid out here for a carbon-capture demonstration at the Pleasant Prairie power plant in Wisconsin. Courtesy of Alstom
