Monday, August 18, 2008

Carbon sequestration, the key to 'clean coal,' might produce more pollutants, study says

Carbon capture and storage, or sequestration, is touted as the way to make coal "clean," or at least eliminate or greatly reduce the climate-changing carbon dioxide that is emitted when it burns. "But trying to capture it and lock it away could allow other repeat offenders to go free," reports Patrick Barry of Science News.

Barry writes, "Power plant emissions that cause acid rain, water pollution and destruction of the ozone layer may actually be made worse by capturing the CO2 and pumping it deep underground, a new study reported online and in an upcoming International Journal of Greenhouse Gas Control suggests. This increase of other emissions is largely because collecting and burying CO2 ... requires additional energy, new equipment and new chemical reactions at the plants. And using current technology, meeting all of these requirements releases extra pollutants." (Emphasis added.)

The author of the study, environmental scientist Joris Koornneef of Utrecht University in the Netherlands, said it is the first “trying to quantify the trade-offs” of carbon sequestration, which takes considerable energy to compress, transported and pumped into underground geological formations. And if that energy comes from coal, the burning of it will generate more sulfur dioxide (SO2) and oxides of nitrogen (NOx).

“The decision to substantially reduce greenhouse gas emissions is going to be intertwined with decisions about how to deal with these other emissions,” said Jim Dooley, an expert in carbon sequestration at the Joint Global Change Research Institute in College Park, Md. (Read more)

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