PG&E Offers the Following Comments with Regard to PRR 984

PG&E offers the following comments with regard to PRR 984:

11.3.2.2Import/Export Hourly Block Schedule Difference Calculation

The CAISO will calculate and publish, for each EIM Entity BAA, the hourly net inter-tie scheduling error of imports and exports whose final tagged schedules differ from either the EIM base schedule or, in the case of the CAISO BAA, the CAISO hourly schedules. The CAISO calculates the hourly scheduling deviations over each month between the 15th day of the prior month and the 15th day of the current month. The CAISO includes the scheduling deviations in the hourly capacity test of the upcoming month.

If an EIM Entity BAA has historical deviations in thenet import/export schedule changes between T-40 and T-20, the CAISO will add an additional hourly block schedule difference to the capacity test. This ensures that the bid range from EIMParticipating Resources cover the difference between net EIM Base Schedules and the Demand Forecast for the Operating Hour.

On a monthly basis, the CAISO will calculate histograms of the percentage of the difference between the net inter-tie schedules at T-40 and final net-tagged inter-tie schedulesat T-20.

In the event the historical net import/export calculation produces anomalous results, the CAISO will set the low histogram percentile and high histogram percentile described below to zero temporarily while it investigates the cause of the anomalous results.

The CAISO will calculate the histograms as follows:

The CAISO will net Imports and exports against each other in each Operating Hour.

If net-tagged imports are greater than net imports in the EIM Base Schedules, the CAISO will add to the affected BAA in the EIM an additional capacity requirement. If net-tagged imports are less than net imports included in the EIM Base Schedules, the CAISO will add to the affected BAA in the EIM an additional capacity requirement.[A1]

If net-tagged exports are greater than net exports included in the EIM Base Schedules, the CAISO will add to the affected BAA in the EIM an additional capacity requirement. If net-tagged exports are less than net exports included in EIM Base Schedules, the CAISO will add to the affected BAA in the EIM an additional capacity requirement.[A2]

The CAISO will include only data for EIM Base Scheduled imports and exports in the histogram; which (i) includes base EIM Transfers, 15-minute intertie schedules, dynamic inter-tie schedules, and pseudo-ties; and (ii) excludesenergy from EIM Transfers.

The CAISO will calculate thenet hourly inter-tie schedules deviationbetween imports and exports scheduled at T-40 and the final tagged imports at T-20 as:

(net actual hourly inter-tie schedule – net base inter-tie schedule) / net base inter-tie schedule

The CAISO will provide each EIM Entity the low and high cutoff percentiles (2.5% and 97.5%, configurable from each histogram).

The CAISO will perform a bid range capacity test every hour. The CAISO will add incremental capacity requirements to the upward capacity test and additional decremental capacity requirements to the downward capacity test. The CAISO will calculate these additional requirements as:

The CAISO calculates additional upward capacity requirement as the highest expectation for net import under-scheduling or net export over-scheduling:

(–1)*low histogram percentile * MAX (0, net base inter-tie schedule) – high histogram percentile * MIN (0, net base inter-tie schedule)

The CAISO calculates additional downward capacity requirement as the highest expectation for net import over-scheduling or net export under-scheduling:

(–1)*high histogram percentile * MAX (0, net base inter-tie schedule) – low histogram percentile * MIN (0, net base inter-tie schedule)

[A1]PG&E suggests that CAISO clarify the language here. The language suggests CAISO will add an additional capacity requirement if the tagged net import is greater than the net import in the base schedule and if the tagged net import is less than the net import in the base schedule. This suggests the CAISO always adds an additional capacity requirement.

[A2]Same issue as above. This language needs to be clarified.