What is Energy?

Energy is the ability to do work. It comes in many different forms:

Energy is in everything. We use energy for everything we do, from throwing a ball to cooking dinner to sending a spaceship to Mars.

Electrical energy is known as a secondary energy source. This is because it takes another form of energy to create it. When we use electric power in our homes, at school, or at work, that electricity can come from many different energy sources. Energy sources are also called "fuels." Here are some sources of energy that help produce electricity.

Energy sources can also be placed into two main groups...Renewable and Nonrenewable.

We use renewable and nonrenewable energy sources to generate (create) the electricity we need for our homes, businesses, schools, and factories. Electricity is used in computers, lights, refrigerators, washing machines, air conditioners, and many other things.

Renewable Energy

When something is renewable, it means that it can be replaced or created over and over again without running out.

Renewable energy sources include:

Nonrenewable Energy

We get most of our energy from nonrenewable energy sources. Nonrewable energy sources are those which cannot be replaced and can eventually run out. Nonrenewable energy sources include the fossil fuels — oil, natural gas, and coal. They're called fossil fuels because they were formed over millions and millions of years by the action of heat from Earth's core and pressure from rock and soil on the remains (fossils) of dead plants and animals. Another nonrenewable energy source is the element uranium. Uranium is used in nuclear energy where atoms are split (through a process called nuclear fission) to create heat and finally electricity.

Fossil fuels are used in other ways besides making electricity. Gasoline and diesel fuel is made from petroleum oil. It powers most of our cars, trucks, and motorcycles. Natural gas is also used to heat homes, dry clothes, and cook food.

Nonrenewable energy sources make up 92% of all energy used in the United States.


*Source: U.S. Energy Information Administration, 2010