PJM will change the way it models combined cycle generators in its least cost dispatch.
The Operating Committee voted overwhelmingly last week to switch to a “composite” model. This will allow combined cycle owners to bid their units in multiple configurations, including duct firing, that reflect the flexibility of the units (i.e., 1×0, 1×1, 2×1, 3×1). Each configuration will have its own parameters (i.e., start time, minimum run time and startup cost).
Under PJM’s current modeling, combined cycle operators must bid as either a combustion turbine or steam unit.
Dave Pratzon, who represents generators, said the change was necessary because combined cycle units have become more prevalent and are more often setting prices. “To my clients the status quo is not a reasonable alternative,” he said.
John Citrolo, of PSEG, also supported the change, saying the current model doesn’t properly compensate generators for combustion turbines starts and stops. “It models the units’ parameters more accurately, gives PJM [dispatchers] more flexibility and compensates owners more fairly,” he said.
The committee chose the composite model over an alternate “additive (pseudo)” option. The additive option would allow combustion turbines to be modeled as separate market units, with the steam turbine modeled as part of the combustion turbines. Pratzon said the additive model was “just a Band-Aid” and was inferior to the composite model.
The proposed change, which will be considered next by the Markets and Reliability Committee, will require software development by PJM’s vendor, Alstom, and changes by generators. The changes are not expected to be implemented before summer 2014.
