Nonrenewable Energy

Nonrenewable energy sources come out of the ground as  liquids, gases and solids. Right now, crude oil (petroleum) is the only naturally liquid commercial fossil fuel. Natural gas and propane are normally gases, and coal is a solid. Coal, petroleum, natural gas, and propane are all considered fossil fuels because they 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.  Uranium is not a fossil fuel.   These energy sources are considered nonrenewable because they can not be replenished (made again) in a short period of time.  Renewable energy sources can be replenished naturally in a short period of time.