How the World Really Works: A Scientist’s Guide to Our Past, Present and Future

by Vaclav Smil

In volume terms (all rates in gigajoules per cubic meter), energy densities are only about 10 for wood, 26 for good coal, 38 for kerosene. Natural gas (methane) contains only 35 MJ/m3—or less than 1/1,000 of kerosene’s density.