Gas turbines are used for generating power in which the exhaust heat is used to power a steam turbine, or for production processes such as paper mills or for example for district heating. In addition gas turbines power compressors or pumps for pumping oil- or gas products over long distances, the pumped product is then also used as fuel for the turbine.
A steam turbine is widely used in combination with one or more gas turbines in a Thermal Power Station or on refineries and petrochemical industry where they usually power compressors. At a Thermal Power Station the residual heat from the gas turbine is used to generate the steam which powers a steam turbine. The benefits of a steam turbine with respect to a gas turbine within the industry that it is easier to vary in speed. Steam turbines are there in high, middle and low pressure variants.