Worldwide demand for petroleum grows steadily every year due to increasing demand in the United States as well as countries with fast-growing economies such as China and India, where the populations are striving to attain higher standards of living and lifestyle. Concern over this increased demand for petroleum in light of worries about reliable supply and global climate change has resulted in the US government passing new Corporate Average Fuel Economy (CAFE) standards and a Renewable Fuels Standard (RFS). The existing mandate in the US to blend ethanol into gasoline (approximately 15 billion gallons annually by 2015) had effectively committed 860 billion gallons of irrigation water in 2005 (approximately 2.4% of U.S. 2005 freshwater consumption) for producing fuel for the light duty vehicle (LDV) transportation sector. It is estimated that by 2030, nearly 2,700 billion gallons of water per year will be consumed and 4,700–6,400 billion gallons withdrawn to produce fuels used in LDVs. Irrigation for biofuels dominates the projected water usage for fuels production, but other alternatives to petroleum gasoline (coal to liquids, oil shale, and electricity via plug-in hybrid vehicles) will also contribute appreciably to future water consumption and withdrawal, especially on a regional level.
Vehicle lightweighting energy use impacts in U.S. light-duty vehicle fleet