FIGURE 1.1 Energy consumption in the United States in 2007 in quadrillions of British thermal units (quads). The figure illustrates the delivery of energy from primary fuel sources, which are shown in the boxes on the left side of the figure, to the residential, commercial, industrial, and transportation sectors, which are shown in the boxes at the center-right side of the figure. Energy is delivered to these sectors primarily in three forms: (1) electricity, which is produced principally from coal, natural gas, and nuclear power, and to a much lesser extent from renewable sources (hydro, solar, wind, and biomass); (2) liquid fuels, principally petroleum, with a small contribution from biomass-derived fuels (e.g., corn ethanol); and (3) natural gas for heating and as an industrial feedstock. Small quantities of coal and biomass are also used as industrial feedstocks. The width of the bars indicates the relative contributions of each energy source; the absolute contribution (in quads) is shown by the numerical labels next to each bar. The bar for electricity represents retail electricity sales only and does not include self-generated electricity. The boxes on the right side of the figure show that a total of about 101.5 quads of energy were consumed in the United States in 2007; about 43 quads were used to provide energy services, and more than 58 quads were “rejected” (i.e., not utilized to provide energy services) because of inefficiencies in energy production, distribution, and use.
Sources: Lawrence Livermore National Laboratory and the Department of Energy, based on data from the Energy Information Administration, 2008a.