What is meant by a Lumpy commitment and how may it affect my transaction or generating unit?
LBMP Prices are determined by an ideal dispatch. In the ideal dispatch, GTs are allowed to be dispatched economically over their entire operating range (0 MWs to Max MWs). The MW schedules are determined in a second ‘blocked’ dispatch. In this dispatch, GTs are dispatched according to their physical generation characteristics. By definition, GTs in this ‘blocked’ dispatch are scheduled at their minimum generation level that translates to their maximum MW limit. As a result, a transaction or generating unit scheduled in the ideal dispatch may have its actual schedule curtailed to compensate for the additional GT scheduled MWs. As an example, assume a transaction has been scheduled at 200 MWs for HB05-HB10 in the ideal dispatch and a 200 max MW GT is dispatched to 0 MWs for HB09-HB10. In the second or ‘blocked’ dispatch the transaction schedule for HB05-HB08 is unaffected. However, for HB09-HB10, the GT must be dispatched to 200 MWs. To compensate for the extra 200 MWs of generation from
