Energy is used throughout the U.S. food system. From the manufacture and application of agricultural inputs, such as fertilizers and feed, to building and powering the machines that turn wheat into bread and hogs into bacon, to making and running the toaster and frying pan used by the consumer at home or by the short order cook at the diner, energy fuels the U.S. food system.

An ERS analysis of food system energy use indicates that, while total per capita U.S. energy consumption fell by 1 percent between 2002 and 2007, food-related per capita energy use grew nearly 8 percent as the food industry relied on more energy-intensive technologies to produce more food per capita for more people.

Examining U.S. food system energy use

Using a framework known as input-output material flow analysis, ERS researchers traced energy use by the U.S. food system, measuring the direct energy used to power machinery, as well as the “embodied” energy used in building and distributing the machinery. Thus, the fuel used to manufacture tractors and to run them on farms was measured. Likewise, the ERS analysis accounts for the electricity to power the microwave oven in the home and the energy used to build and distribute the appliance to consumers.

The input-output analysis framework also includes the energy embodied in other inputs to the food production and marketing system, such as fertilizers, shipping crates, and packaging materials. Energy flow analysis captures both direct and indirect energy flows of the entire food chain, from growing and processing the food, to grinding the plate scraps in a garbage disposal.

The two most recent U.S. benchmark input-output accounts from the U.S. Department of Commerce’s Bureau of Economic Analysis (BEA) show that energy use by the U.S. food system grew at more than six times the rate of increase in total domestic energy use between 1997 and 2002. A projection of food-related energy use based on total U.S. energy consumption and food expenditures in 2007 and on the benchmark 2002 input-output accounts suggests that the U.S. food system accounted for 15.7 percent of total U.S. energy consumption in 2007, up from 14.4 percent in 2002.