It's hard to believe the words “clean” and “coal” could ever be uttered in the same breath. But a high-tech concept for low-emission coal power is increasingly gaining acceptance among industry executives and environmentalists alike. Like it or not, coal already accounts for 50 percent of America's electricity production, and yes, much of that comes from dirty old smog- and CO2-belching plants. The good news is that next-gen technology is on the horizon that could eventually make coal power emissions-free.

Here's how it works: The new coal plants in development do not directly burn coal, but convert it into a gas from which pollutants and greenhouse gasses can be easily filtered. Once the pollution is removed from the exhaust gasses, it is injected thousands of meters underground, in a process known as carbon sequestration.

Although so-called “clean coal” is a technology zealously promoted by the coal industry and the Bush administration, it is also winning favor among environmentalists: Organizations including the Natural Resources Defense Council are beginning to show support for it.

While they oppose the serious environmental consequences of coal mining, they also recognize that coal will be an inevitable part of the world’s energy equation in the near term, particularly given the enormous growth of coal use in India and China, where a new coal plant is being added once every two weeks.

Photo credit: BBC News