Fossil fuels are natural fuels made up of decomposed organic materials that are typically burned to produce steam to turn a turbine, which then produces AC power through a generator. Fossil Fuel energy plants burn either coal, oil or gas in specifically designed combustion chambers to produce the steam.
Technically speaking, fossil fuels are a renewable resource since they are produced naturally. However, many consider them non-renewable because they take millions of years to form, and are being consumed faster than they are produced. Fossil fuel plants are criticized for low efficiency, and for producing pollution. The burning of fossil fuels to turn a turbine often releases harmful gases and solids into the atmosphere, including greenhouse gasses, which were linked to climate change.