According to the United States Energy Information Administration (EIA), only eight percent of the nation's energy comes from geothermal, solar, wind and biomass sources, which are renewable. Non-renewable resources include petroleum, coal, and natural gas. Ores, diamonds and gold are also classified as nonrenewable resources. The U.S. Department of Energy states that oil, gas and coal supply more than 85 percent of the total energy usage for Americans, including nearly 100 percent of fuel for transportation.
Petroleum provides over 40 percent of the nation's energy needs. The United States imports 51 percent of its oil and petroleum products like asphalt, jet fuel, diesel fuel and chemical feed stocks. 99% of the vehicles on our roads use petroleum. The United States Department of Energy's Office of Fossil Energy is responsible for ensuring that the U.S. can make immediate responses to threats to the oil supply and for overseeing that American oil fields are continuously able to produce.
In the mid-20th century, coal was the leading energy resource in the United States. Petroleum and natural gas eventually supplanted coal as the nation's major energy source. However, by the mid-1980s, coal again became the leading fuel source in the United States. The U.S. Energy Information Administration reports that because of its abundance and inexpensive cost, coal produces about 50 percent of the electricity used in the U.S. However, in comparison to oil and natural gas, coal contributes more carbon dioxide per unit of energy.
The renewable resource called geothermal energy comes from heat produced by the Earth. Geothermal energy comes from hot water and hot molten rock (magma) deep near the Earth's core. In addition, shallow water as far down as ten feet below the Earth's surface maintains a constant year-round temperature of around 55 degrees Fahrenheit. Underground pipes extract heated water from the Earth and feed it to a building where a heat pump removes the heat. The system also pulls cool air from the building and pumps it into the Earth.
Between 2007 and 2008, the number of kilowatt-hours generated by wind power worldwide increased about 25 percent. Although the United States surpassed Germany as the leading producer of wind power in 2008, only 1.3 percent of the U.S. electricity need is met from this source. Wind turbines, which can extend as high as 300 feet, have blades attached to a generator that creates electricity. Organized in groups, these turbines can provide significant amounts of power for commercial electrical grids. The system requires winds of at least 8 miles per hour for 18 hours a day to generate electricity.
Biomass fuel comes from plants, grasses, trees, manure and other renewable natural materials. In addition, certain common manufacturing processes produce matter for biomass, including plywood production, lumber and cotton mill activities and paper manufacturing. The fuel produced from this process does not harm the environment because it uses the same amount of carbon dioxide that it draws from the atmosphere. This process has a zero net effect on greenhouse gas emissions.