Combined cycles return as focus for emerging power-system designs

Describes recent technological advances that will improve combined-cycle electric power plants (that integrate gas turbines, heat-recovery boilers, and steam turbines into an efficient generating station that uses less fuel than conventional power plants) which have been hindered by problems with gas-turbine performance and fuel flexibility. Presents diagrams showing the basic combined cycle, popular in the US, using gas-turbine exhaust heat to drive the steam cycle; and a repowering arrangement at a Canadian utility in which the heat-recovery steam generators (HRSGs) are double-sized for flexible operation.