If you turn on a light switch, somewhere in the world, a generator has to produce that electricity. Utility companies did too good a job of making our use of energy simple and seamless. Most people don't know where this instantaneous energy comes from, or the journey it takes to get to them.
The following table breaks down the sources for all our various forms of energy
If it seems a little off balance, that's because it is. We rely heavily on nonrenewable, fossil-fuel-based energy. We suck these fossil fuels out of the ground, and it continues to get harder and harder to find new sources of fossil fuels. In addition, the burning of these fuels causes global warming, pollutes the air and water, and continues to get more expensive. The money spent on finding new sources of oil can be better used to invest in renewable energy.
| Energy Source | Used In | Renewable or Nonrenewable? | Percent |
| Oil | Transportation and manufacturing | Nonrenewable | 38.1 |
| Natural gas | Heating and electricity | Nonrenewable | 22.9 |
| Coal | Electricity | Nonrenewable | 23.2 |
| Nuclear | Electricity | Nonrenewable | 8.1 |
| Propane | Heating | Nonrenewable | 1.7 |
| Biomass | Heating, electricity, and transportation | Renewable | 2.9 |
| Hydropower | Electricity | Renewable | 2.7 |
| Geothermal | Heating and electricity | Renewable | 0.3 |
| Wind | Electricity | Renewable | 0.1 |
| Solar | Light, heating, and electricity | Renewable | 0.1 |
Oil
Americans love cars. Cruising down the open highway is woven into American life, like apple pie and baseball. But all this driving comes with a huge price. The gasoline that Americans use to move these cars is part of a 20-million-barrel-a-day oil habit. More than 55 percent of the oil Americans use is imported from other countries, many of which are economically and politically unstable.
Americans' consumption of oil continuously increases, while the supplies of oil around the world are slowly running out. The pollution from cars and trucks produces more global warming and more air-quality issues. A third of greenhouse gas emissions are from gas burned in automobiles.
Natural gas
Like coal (see the following section), natural gas is a fossil fuel found in large underground deposits. Because it was created millions of years ago, we can't create more.
Although natural gas is clean burning and gives off lower levels of air pollution than coal, gas still has the same issue that all fossil fuels have — what happens when we run out?
Coal
Coal is a combustible mineral found buried deep in the earth. Because coal is a fossil fuel, formed from the ancient remains of plants and dinosaurs, we can't produce more when we run out.
Unlike some of the other energy sources, the United States actually has an overabundance of coal — enough to last for centuries. In fact, the United States has so much of the stuff that it exports coal to other countries.
Coal generates more than half the electricity used in the United States, and is the nation's largest single source of energy. Unfortunately, coal is also the biggest polluter in the United States. It is the largest source of greenhouse gas emissions and mercury poisoning in U.S. air and water. In addition, coal mining is one of the most destructive things people can do to an area.
New technologies are being developed to reduce the pollution from coal production and burning. Sometimes incorrectly referred to as "clean coal," the process crushes the coal into a gas, and uses steam to treat the pollution and gas coming out of the flue. The nonprofit watchdog organization Greenpeace has labeled clean coal technology as "greenwashing" and not solving the real problems associated with coal.
Nuclear
Think of nuclear energy as a fancy way to boil water. Nuclear energy uses radioactive materials to create steam, and that steam powers a generator, which then makes electricity.
Nuclear energy is the second largest source of electricity in the world. It's cheap and doesn't give off any air pollution. Unfortunately, dealing with the radioactive waste created by the creation of nuclear energy is a big problem — no one knows where to put it (or how). Plus, nuclear incidents, like Chernobyl and Three Mile Island, rare as they are, raise safety issues
Hydropower (dams)
Hydropower comes from building a large dam across a river. To make electricity, the dam is opened and water flows into it, spinning the turbines to generate electricity.
Because it uses water, hydroelectric power is considered to be a clean, renewable source of energy. Unfortunately, when the dams are built, low-lying rivers get turned into deep lakes and entire habitats are destroyed.
