Cleaning up coal

COAL IS the fossil fuel that emits both the most toxic mercury and also carbon dioxide, the chief cause of global warming. But coal could be part of the solution to climate change if builders of new plants would use technology that captures and stores CO2 and makes mercury cleanup much simpler.

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Advocates of action on global warming, such as British Prime Minister Tony Blair, should give the highest priority to a new agreement on a carbon cap that includes the United States, China, India, and other countries not limited by the Kyoto Protocol. Such a cap would do far more to curb mercury emissions in this country and worldwide than the weak regulation unveiled by the US Environmental Protection Agency yesterday.

Coal has overtaken cleaner natural gas as the fuel of choice for US utilities because gas supplies are dwindling. By 2012, the United States, which already gets more than half its electricity from coal, is expected to add 72 plants. China is slated to build 562 coal-fired plants by that time and India 213. If all those plants are built with no provisions for CO2 capture and storage, they alone will generate five times the greenhouse gases that the Kyoto signers are pledged to shed by 2012. Last month, the United States failed to support global mercury restrictions.

The prospect is for a sharp speed-up in the experiment with the Earth's climate that mankind has been conducting by spewing CO2, which acts as a solar heat blanket, into the atmosphere. According to David Hawkins, director of the Natural Resources Defense Council's climate center, projected new coal plants would, over their lifespan, add an amount of CO2 equal to 75 percent of all greenhouse gases that have been generated since the start of the Industrial Age. ''We would have eliminated our ability to control global warming," he said last week.

A process in which coal is first gasified before it is used to generate power allows its CO2 to be captured and stored underground and its mercury emissions drastically reduced. But this raises the cost of a kilowatt-hour from 4.5 cents for a conventional coal plant to 6.5 to 7 cents. Utilities will not pay this extra cost unless a rule tells them they have to.

Blair and other advocates of global warming action could have allies among utility CEOs who know that the only thing more expensive than building gasified-coal plants with CO2 controls is adding CO2 controls to a conventional plant after it is running. That might be required if global warming reaches a sudden tipping point and causes such drastic effects on climate or agriculture that action cannot be delayed. Blair, other foreign heads of state, and the private sector should step in and provide the leadership on this issue that a paralyzed Washington cannot.