In a world increasingly concerned with energy costs and supply, so-called clean coal has arisen as a possible solution. While coal has been viewed by many as an old fashioned fuel source, bringing to mind images of smog-filled towns and blackened industrial wasteland, businesses and politicians are encouraging more investment in clean coal technology that reduces some of the harmful emissions that result from the burning of coal.

Coal accounts for half of the electricity production in the United States, and 25 percent worldwide. The United States alone has over 250 billion tons of recoverable coal, an amount estimated to last the country for another 200 years. In 2007, the United States used over 1,046 million tons of coal.

However, emissions from the use of coal are a major source of pollution. Coal accounts for about 36 percent of the United States' carbon dioxide emissions of around 6 billion tons every year. The United States is one of the top emitters of carbon dioxide each year, surpassed only by China. In addition to carbon dioxide, the use of coal gives off other noxious materials such as nitrogen oxides, sulfur dioxides and methane, causing acid rain and possibly contributing to the warming of the earth.