Daniel Yergin of IHS Cambridge Energy Research Associates--author of "The Prize," a history of the oil business--has said U.S. gasoline demand peaked in 2007. Chevron Corp.'s (CVX) Chief Executive Dave O'Reilly said in an earnings call last month that the company has chosen to focus investment on the Pacific Rim, where economies are expected to grow.

The use of fossil fuels to power vehicles has been declining in the U.S. as a result of the economic downturn, greater engine efficiency, increased use of gasoline-electric hybrids, and requirements to include larger amounts of ethanol and other biofuels. As fossil fuel's share of the mix diminishes over time, "we're going to be in the biofuels business," Hayward said.