Coal is the least expensive fossil fuel

Coal and natural gas are by far the most common fossil fuels used to generate electricity in the US. In 2008, electric companies paid almost five times less per unit of energy for coal than for gas[[Roughly $2 per million Btu (a common unit of energy) for coal, and $9.40 per million Btu for natural gas.]]; and by further comparison, if crude oil were as cheap as coal, we would pay under $1.50 per gallon for gasoline at the pump.[[Based upon gasoline price components for 2000-2008 from the Energy Information Administration and an average price per barrel of crude oil of $46 over the same period.]] Because of coal’s low cost and its abundance both in the US and in China and India, which have large populations and are undergoing rapid development, much of the recent increase in atmospheric carbon dioxide comes from burning coal.

The impact of this extra CO2 has been to raise global temperatures, leading to sea level rise, the melting of glaciers and icecaps, more extreme weather events and more.