Introducing the 1S.W501G Single-Shaft Combined-Cycle Reference Power Plant

Driven by the requirements of the US electric power market, the suppliers of power plants are challenged to reconcile both plant efficiency and operating flexibility. It is also anticipated that the future market will require more power plants with increased power density by means of a single gas turbine based combined-cycle plant. Paramount for plant efficiency is a highly efficient gas turbine and a state-of-the-art bottoming cycle, which are well harmonized. Also, operating and dispatch flexibility requires a bottoming cycle that has fast start, shutdown and cycling capabilities to support daily start and stop cycles. In order to meet these requirements the author’s company is responding with the development of the single-shaft 1S.W501G combined-cycle power plant. This nominal 400MW class plant will be equipped with the highly efficient W501G gas turbine, hydrogen-cooled generator, single side exhausting KN steam turbine and a Benson™ once-through heat recovery steam generator (Benson™-OT HRSG). The single-shaft 1S.W501G design will allow the plant not only to be operated economically during periods of high demand, but also to compete in the traditional “one-hour-forward” trading market that is served today only by simple-cycle gas turbines. By designing the plant with fast-start capability, start-up emissions, fuel and water consumption will be dramatically reduced. This Reference Power Plant (RPP) therefore represents a logical step in the evolution of combined-cycle power plant designs. It combines both the experiences of the well-known 50Hz single-shaft 1S.V94.3A plant with the fast start plant features developed for the 2.W501F multi-shaft RPP. The paper will address results of the single-shaft 1S.W501G development program within the authors’ company.