Nonrenewable and renewable energy sources

Energy sources are classified as nonrenewable if they cannot be replenished in a short period of time. Renewable energy sources such as solar and wind can be replenished naturally in a short period of time.

There are four major nonrenewable energy sources:

- Crude oil
- Natural gas
- Coal
- Uranium (nuclear energy)

Nonrenewable energy sources come out of the ground as liquids, gases, and solids. Crude oil (petroleum) is the only commercial nonrenewable fuel that is naturally in liquid form. Crude oil is used to make liquid petroleum products like gasoline, diesel fuel, and heating oil. Propane and other gases such as butane and ethane are found in natural gas and crude oil. They are extracted and stored as liquids and are called liquid petroleum gases.

All fossil fuels are nonrenewable, but not all nonrenewable energy sources are fossil fuels

Coal, crude oil, and natural gas are all considered fossil fuels because they were formed from the buried remains of plants and animals that lived millions of years ago.

Uranium ore, a solid, is mined and converted to a fuel used at nuclear power plants. Uranium is not a fossil fuel, but it is classified as a nonrenewable fuel.