Nonrenewable

Energy sources are of two types: nonrenewable and renewable. Energy sources are considered nonrenewable if they cannot be replenished (made again) in a short period of time. On the other hand, renewable energy sources such as solar and wind can be replenished naturally in a short period of time.

Nonrenewable Basics

The four nonrenewable energy sources used most often are:

• Oil and petroleum products — including gasoline, diesel fuel, and propane
• 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. Natural gas and propane are normally gases, and coal is a solid.

Fossil Fuels Are Nonrenewable, but Not All Nonrenewable Energy Sources Are Fossil Fuels

Coal, petroleum, natural gas, and propane 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 is a nonrenewable fuel.