Combined-Cycle Power Plant

A combined-cycle power plant is an assembly of heat engines that work in tandem from the same source of heat, converting it into mechanical energy and then electricity; the most common land based version is the combined-cycle gas turbine plant. A gas turbine forms the high temperature topping cycle, and its hot exhaust is still hot enough to drive a second, lower temperature steam turbine as the bottoming cycle, usually linked through a heat exchanger so the two cycles can use different working fluids. By drawing power from both cycles, overall efficiency can rise by roughly fifty to sixty percent over a single cycle plant, with modern combined-cycle plants reaching peak steady state efficiencies of about fifty five to fifty nine percent and exceeding sixty percent under ideal conditions. Single cycle plants, by comparison, are limited to efficiencies of about thirty five to forty two percent.