In this section, I give a few very approximate values for various sources of energy and for various uses. The Heat Content table shows the heat that is released when various fuels are burned. A log of oak releases more heat than one of pine simply because it is heavier, not because the wood is different. However, crude oil is somewhat denser, so a bucketful of crude oil will release more heat than a bucketful of gasoline.
Coal always contains mineral impurities.
Methane is the major component of natural gas. There is no natural supply of hydrogen, but hydrogen could be a manufactured fuel, made by removing it from water. It takes a lot of energy to do so, of course, but at least the hydrogen can be transported. The Energy Advocate 1997. All rights reserved.