The steam is created by a boiler in the steam engines, where pure water passes through a series of tubes to capture heat from the firebox and then boils under high pressure to become superheated steam. By far the most widely used and most powerful steam turbines are those driven by steam. Until the 1960s essentially all steam used in steam turbine cycles was raised in boilers burning fossil fuels (coal, oil, and gas) or, in minor quantities, certain waste products. However, modern steam turbine technology includes nuclear steam plants as well as production of steam supplies from other sources.

Steam turbines are widely used for the generation of electricity in a number of different cycles, such as rankine cycle, reheat cycle, regenerative cycle and combined cycle. Steam engines are used to drive compressors. Steam engines are ideal for use in chemical and petrochemical industries. These steam turbines have large applications in electrical power generation applications including refineries, garbage incineration, seawater desalination, co-generation etc. Steam turbine -drive is applicable to large tonnage chillers with an existing source of steam to meet process and space conditioning cooling requirements.

A steam turbine is ideal prime movers for driving machines requiring rotational mechanical input power. They can deliver constant or variable speed and are capable of close speed control. Drive applications include centrifugal pumps, compressors, ship propellers, and, most important, electric generators.

In power plants steam is generated in the waste heat boilers and then used for combined heat and power generation in a backpressure steam turbine. Industrial steam engines cover a wide spectrum of requirements. Industrial applications of steam turbines for combined heat and power generation range from the automobile and petrochemical industries, to sugar, wood processing and paper manufacturing. The steam turbines generate power and heat for these processes.