The steam-electric power station is a power station in which the electric generator is steam driven. Water is heated, turns into steam and spins a steam turbine which drives an electrical generator. After it passes through the turbine, the steam is condensed in a condenser. The greatest variation in the design of steam-electric power plants is due to the different fuel sources.
Almost all coal, nuclear, geothermal, solar thermal electric power plants, waste incineration plants as well as many natural gas power plants are steam-electric. Natural gas is frequently combusted in gas turbines as well as boilers.  The waste heat from a gas turbine can be used to raise steam, in a combined cycle plant that improves overall efficiency.
Worldwide, most electric power is produced by steam-electric power plants. The only widely used alternatives are photovoltaics, direct mechanical power conversion as found in hydroelectric and wind turbine power as well as some more exotic applications like tidal power or wave power and finally some forms of geothermal power plants. Niche applications for methods like betavoltaics or chemical power conversion (including electrochemistry) are only of relevance in batteries and atomic batteries. Fuel cells are a proposed alternative for a future hydrogen economy.