Energy causes things to happen around us. Look out the window. The sun radiates light and heat energy. It helps plants to grow. At night, lamps in our home use electrical energy to light our rooms. When a car drives by, it is being powered by gasoline, a type of stored energy. The food we eat contains energy. We use that energy to work and play.

Energy can be found in a number of different forms. It can be chemical energy, electrical energy, heat (thermal energy), light (radiant energy), mechanical energy, and nuclear energy.

We use energy to do work, especially electric energy. Electricity lights our cities. Combustion energy powers our vehicles, trains, planes and rockets. Electric and gas (thermal) energy warms our homes, cooks our food, plays our music, gives us pictures on television. Energy powers machinery in factories and tractors on a farm.

Everything we do is connected to energy in one form or another....

What are the Different Types of Energy?

Renewable energy sources:

These sources are constantly renewed or restored and include wind (wind power), water (hydropower), sun (solar), vegetation (biomass), and internal heat of the earth (geothermal). About 9.0 percent of electricity in the U.S. is generated from renewable sources.

Nonrenewable energy sources:

These are natural resources that cannot be replenished (fossil fuels such as oil, gas, and coal). About 71.5 percent of electricity in the U.S. is generated from nonrenewable sources. In addition to renewable and nonrenewable energy sources, about 19.5 percent of electric power in the U.S. is generated by nuclear power plants. However, operating such plants poses significant nuclear waste disposal problems; consequently, there are no current plans to build more. Most electricity in the United States is generated by burning nonrenewable fossil fuels and there is a limited amount of these energy sources.

Why is Energy Conservation Important

Because of the limited amount of nonrenewable energy sources on Earth, it is important to conserve our current supply or to use renewable sources so that our natural resources will be available for future generations.

Energy conservation is also important because consumption of nonrenewable sources impacts the environment. Specifically, our use of fossil fuels contributes to air and water pollution. For example, carbon dioxide is produced when oil, coal, and gas combust in power stations, heating systems, and car engines. Carbon dioxide in the atmosphere acts as a transparent blanket, that contributes to the global warming of the earth, or "greenhouse effect." It is possible that this warming trend could significantly alter our weather. Possible impacts include a threat to human health, environmental impacts such as rising sea levels that can damage coastal areas, and major changes in vegetation growth patterns that could cause some plant and animal species to become extinct.

Sulfur dioxide is also emitted into the air when coal is burned. The sulfur dioxide reacts with water and oxygen in the clouds to form precipitation known as "acid rain." Acid rain can kill fish and trees and damage limestone buildings and statues.

You can help solve these global problems. In the U.S., the average family's energy use generates over 11,200 pounds of air pollutants each year. Therefore, every unit (or kilowatt) of electricity conserved reduces the environmental impact of energy use.