A power plant that uses at least two generation processes, which results in greater efficiency. This type of plant uses both gas and steam turbines. The gas turbine generator uses natural gas to generate electricity. The steam turbine uses waste heat (exhaust) from the gas turbine to make steam that generates additional electricity. By using waste heat that would otherwise be lost, a combined cycle plant process increases the plant's efficiency.

These plants generally have a higher heat rate than coal-fired and single cycle plants.