To many people who are passionate environmentalists, the words “clean” and “coal” couldn’t be more polarized opposites. The thought of coal directly implies powerplant smokestacks belching carbon dioxide emissions and other pollutants.
Certainly, it is true that coal-burning powerplants have historically been largely responsible for high quantities of sulfur dioxide and nitrous oxide emissions that contribute to acid rain and local air quality non-attainment issues (e.g., haze, surface ozone). And, it remains true that coal powerplants continue to be perhaps the most important single contributor to global warming, by virtue of their high CO2 emissions.
But, is a no-tolerance anti-coal perspective justified on an environmental basis? In my mind, no. In fact, it is theoretically possible to reconcile the concept of zero-emissions coal utilization. This entails the use of an integrated gasifier coal combined-cycle (IGCC), along with carbon sequestration.
This is the vision of the FutureGen Alliance. FutureGen Alliance Announcement This initiative, announced in late 2005, embraces many of the largest and most important parties in coal-fired generation to develop a standardized coal-to-electricity technology that produces no air emissions. The combined-cycle part of the technology is well-understood, having been widely utilized for many years now. In contrast, there are two relatively new technologies that remain to be commercialized for the zero-emissions coal vision to be realized:
The first is gasification technology — converting coal to a synthetic gas (“syngas”) similar to natural gas for use in the combined-cycle. There have been a number of gasification technologies employed for decades, and they work reliably, but none have yet to achieve the holy grail of being deemed “commercially economical”.
The second is carbon sequestration technology — capturing CO2 emissions from the exhaust stream and then injecting it underground. Again, the science is well understood, but the economics of carbon sequestration have always been challenging, particularly because of the intensive energy requirements.
If these two technologies can be commercially improved, making sequestered-IGCC economically-viable, then our future energy and environmental situations are much more assured. We have plenty of coal to last for well more than 100 years, and if we can use it in an environmentally-benign way, it seems like a no-lose resource for us to employ, until we can get to some energy system (solar with storage? hydrogen fuel cells? fusion?) that can realistically serve the human species for millenia.