All power plants, from on-site generators to large-scale regional providers, essentially work by concentrating a diffuse energy rather than harvesting it. Often, energy from heat is among the easiest to concentrate. A fossil fuel power station creates this heat by burning oil, natural gas, or coal.
Most commonly, a fossil fuel power station operates by steam generation. Coal, natural gas or petroleum is burned to heat water and produce steam. The steam is then forced over the blades of a turbine, causing the attached rotor to spin. The spinning rotor powers a generator, which creates electricity that can be harvested. These plants typically recover about one-third of the thermal energy of the burning fuel.
More rarely, a fossil fuel power station can be powered by burning the fuel directly. In these cases, the hot air created by the burning process spins the turbine. These plants have the benefit of being powered up and down more rapidly. The reduced water use also eases environmental damage. Negatively, these plants are less efficient than steam-powered units.
Coal remains the popular choice for a fossil fuel power station. In the United States, approximately 50 percent of all electricity comes from coal plants. Other countries such as South Africa and Poland are even more reliant on coal, with over 90 percent of all power originating from the fuel.
Coal plants are abundant for many reasons. In most areas, coal is by far the most readily-available fuel. This often makes it the most cost-efficient option as well. In addition, coal plants were the earliest built, and most are still in operation. Often, building an expensive new plant to replace a still-operative facility is not economically feasible.
Second in popularity among fossil fuels is natural gas. In certain areas, natural gas is almost as abundant as coal and, on average, cost-comparable. Gas weighs less than other fossil fuels and often is easier and less expensive to transport. In emergency situations, the flow of natural gas can generally be immediately stopped. Finally, natural gas burns cleaner than oil or coal and is, thus, largely considered to be a more environmentally-responsible choice for reducing air pollution.
A petroleum fossil fuel power station works by burning crude oil. Although these power plants account for less than 10 percent of the electricity produced in North American countries, they are the natural choice for areas where oil is more plentiful. Sometimes, very small-scale power stations can work on a combustion model very similar to a car engine. In these cases, petroleum is the most logical choice.