ABSTRACT

The United States faces energy shortages and increasing energy prices within the next few decades (Duncan, 2001). Coal, petroleum, natural gas, and other mined fuels provide 75% of U.S. electricity and 93% of other U.S. energy needs (USBC, 2001). On average, every year each American uses about 93,000 kWh, equivalent to 8000 L of oil, for all purposes, including transportation, heating, and cooling (USBC, 2001). About 12 kWh (1 L of gasoline) costs as much as $0.50, and this cost is projected to increase signifi cantly in the next decade (Schumer, 2001).