Earth: The Densest Energy of All

Earth held the densest energy of all, buried and waiting for humanity to dig deep enough to find it. Each layer down, coal, then oil, then uranium, unlocked an order of magnitude more energy than the one before it.

Key Milestones

• Gunpowder and explosives, roughly the 9th century AD in China. A mineral-derived chemical reaction released energy in an instant rather than a slow burn, transforming warfare permanently and, we would argue more importantly, mining and construction.
• Coal and oil, with coal from roughly the 1760s and oil from 1859 at the Drake Well. Earth gave up energy denser than anything humanity had burned before, and the Industrial Revolution ran on it.
• Nuclear fission, 1942, with the first controlled reactor. Splitting the atom unlocked an energy density orders of magnitude beyond anything chemical combustion could offer.

The Energy, Social, and Economic Impact of Earth

The clearest way to see this arbitrage is to compare how much energy each fuel actually holds. A kilogram of wood yields about 16MJ (megajoules) of energy, which is 16,000 kJ, the unit on a nutrition label. Coal yields roughly 24MJ per kilogram; oil, about 45MJ. Uranium-235, fully fissioned, yields on the order of 86 million MJ per kilogram, millions of times denser. We believe that density is exactly why coal took over the world's energy supply so quickly once it arrived: its share of world primary energy jumped from just 6% in 1850 to 64% by 1900.

View chart in the full report

View chart in the full report

Gunpowder deserves its own mention here, because it was the first time humanity extracted energy from the earth specifically to release it all at once, the same instinct that echoes forward through mining explosives and, eventually, the atom itself.