Non-renewable energy means the energy source will eventually run out. Most of the non-renewable energy sources belong to the fossil fuel category. Coal, natural gas, crude oil and liquid petroleum gas are examples of non-renewable energy sources.
Carbon is the main element in fossil fuels; they were formed 300 to 360 million years ago. All fossil fuels are created through a similar process. Animals and plants that died were covered with sediment, rocks and seabed, and over time, the heat and pressure turned the remains into fossil fuels. There are huge underground pockets of coal, petroleum and natural gas all over the world. Non-renewable resources are easy to get to and relatively inexpensive to obtain as well, which makes them a valuable source of energy.
Burning fossil fuels can be very harmful because the particles released pollute the air, land and water. The use of these fuels also adds to the greenhouse effect, causing global warming as these gases don't allow the heat to escape the atmosphere. A lot of fossil fuels are used to produce electricity. According to the Central Intelligence Agency, the United States produces 66 percent of it's electricity with fossil fuels and another 8% from nuclear power.