“Clean coal” came on the scene in the mid-1980s when environmentalists worried more about acid rain and smog than global warming. It encompasses a handful of technologies that try to reduce pollution from burning coal, which is laden with sulfur, mercury, smog-inducing particulates and nitrogen oxides and carbon. Tampa Electric calls it “clean coal” but other experts call it “cleaner coal” or “advanced coal technology.”

In 1985, amid concerns that “acid rain” pollutants were damaging forests and watersheds, the U.S. Department of Energy started a Clean Coal Technology Program to spur investment in technology that removed the sulfur, nitrogen and particulates emitted from coal plants. Tampa Electric was one of the first to step forward, building a 250-megawatt “clean coal” plant dubbed Polk One, using a technology called Integrated Gasification Combined Cycle, or IGCC.

The Department of Energy calls it “one of the most advanced – and cleanest – coal power plants in the world” compared to traditional coal plants.
What about the carbon?

“Clean coal” experts say that it will be easier to capture carbon at an IGCC plant than a pulverized coal plant, because carbon can be removed from the compressed gas, instead of captured as it swirls out of a giant stack. The challenge is what to do with carbon once it is removed. TECO and researchers from the University of South Florida suggest it could pump the carbon deep underground, to store it indefinitely. But there are a lot of unanswered questions.