bFor metric units (e.g., kWh) the metric prefix is used; for Btu, the “value” multiplier is used, as shown in Table F.1, “Metric Prefixes.”
cData from Table 1-11: Number of U.S. Aircraft, Vehicles, Vessels, and Other Conveyances, available at http://www.bts.gov/publications/national_transportation_statistics/html/table_01_11.html.
dData from Table MF21 (for motor fuel use) and Table MV1 and MV9 (for private and commercial auto stock) in Highway Statistics 1998, available at http://www.fhwa.dot.gov/ohim/ohimstat.html. Table 1.10 for average annual miles in Monthly Energy Review, DOE/EIA-0035(2000-04), April 2000.
eData from Residential Energy Consumption Survey, available at http://www.eia.doe.gov/emeu/.
fData from Table 7.5 in Monthly Energy Review, DOE/EIA-0035(2000-04), April 2000.
gSee Tables 2.6 and 7.5 in Monthly Energy Review, DOE/EIA-0035(2000-04), April 2000. In 1999, the U.S. electric grid consumed 34.5 quads of source energy to generate and sell 3,300 TWh of electricity. This yields a “heat rate” of 10,500 Btu/kWh.