Repowering Application Considerations

As utilities plan for load growth in the 1990s, they are faced with the difficulty of choosing the most economic generation while subject to a number of challenging constraints. These constraints include environmental regulations, particularly the new Clean Air Act, risk aversion, fuel availability and costs, etc. One of the options open to many utilities with existing steam units is repowering, which involves the installation of gas turbine(s) and heat recovery steam generator(s) (HRSG) to convert the steam plant to combined-cycle operation. This paper takes an overall look at the application considerations involved in the use of this generating option, beginning with a summary of the size ranges of existing steam turbines that can be repowered using the GE gas turbine product line. Other topics covered include performance estimates for repowered cycles, current emissions capabilities of GE gas turbines, approximate space requirements and repowering economics.