Structural representation of South African coal courtesy of Daniel van Niekirk / Jonathan Mathews
—By David Pacchioli
Scan the list of 21st-century energy sources, and you’re in for a jarring surprise. Solar. Wind. Nuclear. Hydrogen. Biomass. Coal.
Coal? The earthbound rock of our ancestors? Maker of mines and museums, steel and smog? Fuel of the Industrial Revolution? How’d that get on the list? Pennsylvanians have a special feeling for coal. It’s in our bones—and in our lungs. We know the complex, defining role it has played in our state’s, our nation’s, history. But even we tend to think of coal in the past tense. “ ‘Isn’t coal dead?’ I’ve been hearing that for a long time,” says Harold Schobert, professor of fuel science at Penn State. But in a world whose oil is running out, where renewable energy technologies are full of promise but not yet ripe, coal is back. In fact, it’s the new black: the other hydrocarbon. In some respects, of course, coal has never been away. Coal-burning power plants produce fully half of American electricity. With the price of oil fluctuating wildly, however, coal has achieved a whole new level of attention, its cheapness and availability making it attractive as the choice for “energy independence.” The U.S. sits on vast reserves of the stuff—200 years’ worth, by most estimates, and coal is already fueling economic booms in China and India, who possess it in similar quantities. Coal, its proponents say, is a fuel for the present, and for at least the near-term future. This kind of talk makes a lot of people anxious, and with good reason. For although government legislation has largely curbed smokestack pollutants and acid rain in the U.S. since the 1990s, coal-burning power plants remain the leading manmade source of the greenhouse gases implicated in global warming. According to EPA data, annual carbon dioxide emissions from these plants are greater than the emissions from all cars, trucks, planes, trains, and other forms of transportation combined. Per unit of energy, coal emits far more carbon dioxide than its fellow fossil fuels, oil and natural gas. Yet most experts agree that coal will be used increasingly for at least the first half of the coming century, both in the U.S. and around the world. The question, then, is whether the environmental impacts of that use can be mitigated. Can new conversion and “carbon-capture” technologies and new government regulations render coal’s use “carbon-neutral”? Can coal clean up its act? Penn State scientists and engineers are at the forefront of those who are working to find out.