| Power School
Traditional fuels
Coal
The United States has the largest supply of minable coal in the world. This coal comprises 95% of our fossil energy reserve. One ton of coal produces 2,000 kWh of electricity. That's enough to power one average home for three months. Although abundant and relatively cheap, coal has a major drawback. Burning it emits harmful greenhouse gases. And burning it "clean" is as expensive as using renewable energy sources.
Natural gas
Natural gas is mostly methane. It comes from deep underground reservoirs, often found very close to oil. More than 50% of homes in the United States depend on natural gas for heating. Natural gas is the cleanest burning fossil fuel. It produces no solid waste, emits less than 1% of the sulfur dioxide and particle emissions produced by coal, and emits 85% less nitrogen oxide than a "clean" coal plant.
Natural gas accounts for 25% of all the energy produced in the United States.
Nuclear
First developed in the 1940s, nuclear energy now accounts for 15% of the electricity generated in the United States. More than 100 nuclear power plants dot the country. Although nuclear energy produces no harmful greenhouse gases, spent nuclear fuel is radioactive. Currently, spent fuel resides at reactor sites.
Creating nuclear energy costs about as much as burning coal or natural gas. However, building new nuclear reactors has been prohibitively expensive.
Oil
The United States imports most of its oil from OPEC countries. This makes supply and pricing uncertain. It is expensive to burn and dirtier than natural gas.
Oil accounts for only 10% of the electricity produced in the United States.
Hydropower
Hydropower comes from dams. Dams create electricity by guiding water down a chute and through a turbine. Ideal sites for dams include swift-flowing rivers and streams, particularly in mountainous regions and areas with heavy rainfall. Only 2,400 of the nation's 80,000 dams generate electricity. Those that do generate 10% of the electricity in the United States. Many other dams could be retrofitted to produce electricity.
Wind
Generating electricity from the wind is quickly growing in popularity around the world. The windmill powers a turbine that generates electricity. Wind power creates no environmental pollution and has little negative impact on the land. Three wind farms in California generate more than 90% of wind energy in the United States.
Wind turbines, however, can be noisy. Many communities do not want them located near homes. Others are concerned about the possible impact on bird life.
Solar
Creating energy from sunlight requires solar cells. Solar cells turn sunlight directly into electricity. Alth the technology of solar cells has come a long way, the cost of generating and distributing solar energy is very high.
Biomass
Biomass includes wood and wood wastes, agricultural crops and their waste byproducts, municipal solid waste, animal wastes, waste from food processing, aquatic plants and algae, and landfill gases such as ethanol and methanol.
Burning biomass emits fewer harmful gases than burning fossil fuels. It also reduces the amount of waste sent to landfills and lessens our dependence on foreign fuels.
 |
