Total U.S. energy production reached 81.7 quadrillion British thermal units (quads) in 2013, enough to satisfy 84% of total U.S. energy demand, which totaled 97.5 quads. Natural gas was the largest domestically produced energy resource for the third year in a row and, together with the other fossil fuels (coal, crude oil, and hydrocarbon gas liquids), accounted for more than three quarters of U.S. energy production. In total, the United States consumed 97.5 quads of energy, 82% of which was fossil fuels. Renewable and nuclear energy made up 10% and 8%, respectively, of U.S. energy consumption.
The portion of U.S. energy consumption supplied by domestic production has been increasing since 2005, when it was at its historical low point (69%). Since 2005, production of domestic resources, particularly natural gas and crude oil, has been increasing as a result of the application of technologies that can develop harder-to-produce resources. At the same time, reduced road travel, improved vehicle efficiency, and competition among fuels for electric power generation have limited consumption of petroleum and coal.