Conventional energy sources

The group of conventional energy sources is one of the three main type of energy sources.

We are using the conventional / nonrenewable energy sources every day in different form: coal, natural gas, petrolium, electricity.... The conventional sources are not able to recreate in a short period of time.
Energy sources help us, through the different ways, to get energy generate power.
Most of the energy energy we used is from nonrenewable energy sources: oil, natural gas, and coal.  We know them as fossil fuels because they were formed over millions and millions of years by the action of heat from the Earth's core and pressure from rock and soil on the remains (or "fossils") of dead plants and animals. 
Another nonrenewable energy source is the element uranium, whose atoms we split (through a process called nuclear fission) to create heat and ultimately electricity
Nitrogen is a chemical element and it is a common element in the universe and also is used as energy source.
We use all these energy sources to generate the electricity we need for our homes, businesses, schools, and factories.
Electricity "feeds" our computers, lights, refrigerators, washing machines, air conditioners ....
The gasoline is made from oil.  We use energy of the gasoline to run our cars. We use energy to cook on an outdoor grill or soar in a beautiful hot-air balloon.  The propane, that we use to cook or to fill the air balloons, is made from oil and natural gas.
Fossil fuels are easy to use to generate energy because they only require a simple direct combustion.
However using fossil fuels is a problem bacause of their environmental impact. Their combustion leads to a great deal of air pollution. Burning fossil fuel produces carbon dioxide, which contributes to the "greenhouse effect" - global warming.
Fossil fuels are nonrenewable, but not all nonrenewable energy sources are fossil fuels.