For a Unit, this column shows the incremental heat rate for the segment currently dispatching that hour. If the unit is running at minimum or is offline, the incremental heat rate of the first dispatchable segment will be reported.
Note that for commitment units the Committed Heat Rate is only applied to the dispatchable portion of the resource, thus it is possible for this value to report the Heat Rate at Minimum when the units is as Minimum Capacity.
Incr Heat Rate Column