1.1. thermal power plants: also called combustion power plants, they operate with energy produced by a steam boiler fueled by coal, natural gas, heating oil, as well as by biomass. The steam activates a turbine which, in turn, drives an alternator to produce electricity
2. Petroleum
2.1. Petroleum is a naturally occurring liquid found beneath the earth's surface that can be refined into fuel.
3. Coal
3.1. Coal is a hard rock which can be burned as a solid fossil fuel. It is mostly carbon but also contains hydrogen, sulphur, oxygen and nitrogen. It is a sedimentary rock formed from peat, by the pressure of rocks laid down later on top.
4. Natural gas
4.1. Natural gas (also called fossil gas; sometimes just gas), is a naturally occurring hydrocarbon gas mixture consisting primarily of methane, but commonly including varying amounts of other higher alkanes, and sometimes a small percentage of carbon dioxide, nitrogen, hydrogen sulfide, or helium.
5. Hydroelectric energy
5.1. thermal power plants: also called combustion power plants, they operate with energy produced by a steam boiler fueled by coal, natural gas, heating oil, as well as by biomass. The steam activates a turbine which, in turn, drives an alternator to produce electricity
