Energy content of biofuel (J/kg) or equivalent units. Energy density is the amount of energy stored in a fuel per unit volume, expressed in SI units as joule per litre (J/L) or equivalent units. The table below includes entries for popular substances already used for their energy, or being discussed for such use. The second column shows specific energy, the energy content in megajoules per unit of mass in kilograms, useful in understanding the energy that can be extracted from the fuel. The third column in the table lists energy density, the energy content per liter of volume, which is useful for understanding the
Energy slave industrial economy, and therefore 1 ES times a constant that converts to work accomplished = 1 human labor unit. Energy slave An energy slave is that quantity of energy (ability to do work) which, when used to construct and drive non-human infrastructure (machines, roads, power grids, fuel, draft animals, wind-driven pumps, etc.) replaces a unit of human labor (actual work). An energy slave does the work of a person, through the consumption of energy in the non-human infrastructure. The term was first used by R. Buckminster Fuller in the caption of an illustration for the cover of the February 1940