Before revision: Primary energy fallacy Sankey diagram for the United States 2016 shows that 66.4% of primary energy ends up as waste heat Where primary energy is used to describe fossil fuels, the embodied energy of the fuel is available as thermal energy and around two thirds is typically lost in conversion to electrical or mechanical energy.
After revision: Conversion factor conventions Sankey diagram for the United States 2016 shows that 66.4% of primary energy ends up as waste heat Where primary energy is used to describe fossil fuels, the embodied energy of the fuel is available as thermal energy and around two thirds is typically lost in conversion to electrical or mechanical energy.