The first coal-fired power plant designed from the ground up to capture carbon emissions began operations this month in Spremberg, Germany. The new plant is known as the Schwarze Pumpe pilot plant. It replaces a Communist-era power station so notorious for its pollution that Spremberg was nicknamed "Stinky Town." Vattenfall, a Swedish power company, constructed and operates the new plant.

Spremberg's new facility is on the small side: It generates only 30 megawatts of power. In order to capture carbon emissions, the plant's operations are a little more complicated than "burn coal and get energy." Instead, the coal is burned in a special environment where nitrogen has been removed from the air. The environment is oxygen-rich and its combustion produces carbon dioxide and water vapor as waste. The process is repeated, effectively distilling the carbon dioxide into a gas that can be 98 percent carbon dioxide. That gas is cooled and liquefied and will eventually be deposited underground in a depleted gas field.

Vattenfall says that, at least in theory, the plant will produce almost zero pollution. Lars Strömberg, the vice president of Vattenfell, told Technology Review that absolutely no emissions is impossible, "but we will come very, very close to this target."

The price of minimal emissions, so far, has been efficiency. The process of compressing and transporting carbon dioxide requires significant energy, as does the removal of nitrogen from the air used to combust coal. Vattenfall is using the Schwarze Pumpe plant as a pilot and hoping to improve efficiency through a variety of measures. The testing program is expected to last three years. Beyond improving efficiency, Vattenfall will also explore exactly what proportion of carbon emissions can be eliminated in a practical setting.

If all goes well in the testing phase, Vattenfall plans to scale its process to a larger demonstration plant capable of generating between 300 and 500 megawatts by 2015. The company hopes to have 1,000-megawatt commercial plants in place after 2020. The pilot plant cost approximately 70 million euros to construct.

Clean coal continues to face some controversy, since it runs counter to the prevailing feeling that rather than spending money on coal, energy companies should focus on renewable resources. Nevertheless, clean coal seems preferable to efforts to drill offshore. If Vattenfall can make coal a practical option, with the effective elimination of emissions, it may prove a transition technology worth considering.

Image — Vattenfall