Coal is dirty. We all know how bad it is on the environment. The latest idea of sequestering the greenhouse gases is just a feable attempt to keep an industry alive. After all coal is still the U.S. number one energy source. Unfortunately, the habitat that coal ruins along with the CO2 that WILL eventually get into the atmosphere now or later, makes coal one of the worst energy sources we use today. Slowly but surely Solar, wind, and geothermal will surely phase out this scurge on the environment.
Natural Gas is the cleanest of the three fossil fuels. It takes little or no refining before it can be used to generate energy. Unfortunately it is still a big greenhouse gas emitter and is of course not in a renewable supply. While it may be the best of the worst of our energy sources, its still not what will get us through this century and needs to be phased out.
Oil is the biggest commodity our world has ever known. Not gold or silver or diamonds have proven more valuable than the flexible way in which we extract the energy from oil. Oil is used in basically every industry. From CD's to engine oil, Crude Oil (Oil, unrefined from the ground) is the foundation for much of our industrialized world. The transportation capabilities that oil has given us would have been hard to imagine just 100 years ago. Creating an independance from this particular substance is going to be one of the great challenges of the twenty-first century.