"Energy use is pervasive throughout the U.S. economy. Households and businesses use energy from oil, natural gas, coal, nuclear power, and renewable sources (such as wind and the sun) to generate electricity, provide transportation, and heat and cool buildings. In 2010, energy consumption represented 8.4 percent of U.S. gross domestic product. Disruptions in the supply of commodities used to produce energy tend to raise energy prices, imposing an increased burden on U.S. households and businesses. Disruptions can also reduce the nation's economic output and thus people's income. This paper examines energy security in the United States--that is, the ability of U.S. households and businesses to accommodate disruptions of supply in energy markets--and actions that the government could take to reduce the effects of such disruptions. The vulnerability of the U.S. economy to disruptions in the supply of a particular energy source depends on the importance of that energy source to the economy. More than 80 percent of the energy consumed in the United States comes from oil, natural gas, or coal."
U.S. Congressional Budget Office: http://www.cbo.gov/