Combined cycle power plant, when used as a generic term, refers to a plant which converts heat into mechanical energy in a combined gas and steam turbine process. Combined cycle processes with coal gasification or coal combustion turn solid fuels into a fuel gas or a hot pressurised gas which is then used in the gas and steam turbine processes. Coal-fuelled combined cycle plants will be discussed in detail in the following sections. A start will be made by describing the basic technical features and the characteristic data of combined cycle power plants fuelled by natural gas for the purposes of comparison to coal.