Combined Cycle Unit Law and Legal Definition

According to 10 CFR 500.2 [Title 10 Energy; Chapter II Department of Energy; Subchapter E Alternate Fuels; Part 500 Definitions], the term combined cycle unit means “an electric power generating unit that consists of a combination of one or more combustion turbine units and one or more steam turbine units with a substantial portion of the required energy input of the steam turbine unit(s) provided by the exhaust gas from the combustion turbine unit(s).”

Substantial amounts of supplemental firing for a steam turbine or waste heat boiler to improve thermal efficiency will not affect a unit's classification as a combined cycle unit.