Comments on Final Proposal

WEIM sub-entity scheduling coordinator role

Comment period
May 19, 08:00 am - May 26, 05:00 pm
Submitting organizations
View by:

Platte River Power Authority
Submitted 05/25/2021, 12:11 pm


Carol Ballantine (

14. Please provide your organization's overall position on the final proposal.
No position

Generally, supports

15. Please provide your organization's comments on the clarifying language in the final proposal.


Platte River Power Authority (Platte River) appreciates the California Independent System Operator’s (CAISO) efforts to develop its May 18, 2021, Western EIM Sub-Entity Scheduling Coordinator (SESC) Role Final Proposal (Proposal) and generally supports the concepts in the Proposal.  

Platte River’s comments to the Proposal are (1) Expectations added for the use of manual dispatch should apply to EIM entities and EIM sub-entities alike, and (2) transmission information and governance is essential to effective market operations and may not be adequately addressed in the Proposal.

Manual dispatches

Platte River agrees with the expectations added for the use of manual dispatch but disagrees that this language should only apply to EIM sub-entities and not also to EIM entities. The language states in part that, “[T]he CAISO expects the use of [manual dispatches] to be for reliability related actions in accordance with previously agreed upon circumstances and conditions, such as participation within a reserve sharing group or similar operational purpose.” Platte River previously requested in its February 18, 2021, comments to CAISO’s January 21, 2021, Revised Straw Proposal similar language to address both EIM sub-entities' and EIM entities’ use of manual dispatch, which was not adopted. The use of manual dispatches by either an EIM entity or an EIM sub-entity could have far reaching, material impacts on other market participants and should only be used by all EIM market participants in accordance with the language cited above.

Transmission information and governance

Platte River supports the additional language in the “Roles and Responsibilities,” the “System Access – BAAOP,” and “Outage Management” sections regarding the submittal of transmission information and roles and responsibilities related to transmission use. However, due to the broad nature of the language in the Proposal, Platte River is not sure that the interaction between EIM sub-entities, EIM entities, and CAISO related to transmission has been fully addressed. Platte River reiterates the redlines and comments it submitted to Sections 29.17 and 29.26 of the April 15, 2021, version of the redlined Tariff and Section 2.5 of the April 15, 2021, version of the redlined EIM Sub-Entity Agreement and asks CAISO to ensure that Platte River’s redlines and comments have been appropriately addressed in the Proposal. How transmission information is communicated and how transmission use is governed needs to be clear to facilitate effective communication and correct market operations.

Xcel Energy
Submitted 05/26/2021, 04:00 pm


Steve Szablya (

14. Please provide your organization's overall position on the final proposal.
Support with caveats

Xcel Energy appreciates the time and effort provided by the CAISO and all stakeholders in this initiative. Xcel Energy also appreciates the additional redline commentary provided by the CAISO in feedback to various concerns raised by stakeholders. Generally, Xcel Energy supports the descriptions and functions put forth by the CAISO and refined by this stakeholder process. 

15. Please provide your organization's comments on the clarifying language in the final proposal.

At this time and based on the commentary provided by the CAISO, Xcel Energy expects that the CAISO has fully and deliberately considered the mechanisms through which sub-entity settlements and coordination will occur.  However, it remains unclear to Xcel Energy the method by which the under and over scheduling charges will be allocated to the sub-entities by the CAISO without the CAISO market having knowledge of the sub-entity interchange quantities as observed prior to the start of the EIM hour.

The bilateral interchange position as it relates to base schedules is a fundamental component of the Balancing Area balanced resource plan. The interchange position is utilized first as a component of the forecast resource position prior to the operating hour, and second as a component of assessing the retrospective resource position. This proposal indicates (as quoted below) the retrospective base schedule resource position will be determined at the sub-entity level. It seems to follow that the sub-entity interchange quantity would be necessary to determine any interchange (resource or obligation) component of a sub-entity base schedule position accurately and independently of other sub-entities.

For reference, the CAISO has written:

“If the net balancing authority area load deviation exceeds any of the penalty thresholds, the CAISO settlement shall calculate the over-scheduling and under-scheduling charges at the EIM sub-entity level based on the sub-entity deviations at the associated over/under scheduling LAP penalty price. If the balancing authority area passes the balancing test or is within the threshold, the EIM sub-entity level will be allocated a portion of the over-scheduling and under-scheduling total costs based on the metered demand within the sub-entity and the sub-entity’s submitted base schedule.”

If the over and under-scheduling charges are calculated using an inaccurate (i.e. by assumption or inference of) sub-entity interchange schedule quantity, this may result in inaccurate calculation of the sub-entity's retrospective resource position. Said differently, it may be difficult to accurately determine the cost-causation of under or over-scheduling penalties without knowing the total quantity of sub-entity resources and obligations.  To resolve this, Xcel Energy suggests the CAISO consider a mechanism by which sub-entity hourly interchange values may be submitted to the CAISO MRI-S. The market balancing tests may still be performed at the EIM Entity level, remaining consistent with the CAISO’s intention to perform RSE at the BAA level. Then, by including sub-entity interchange values in MRI-S, the market settlements engine might have better information by which allocation of over and under-scheduling penalties might be performed. 

Back to top