Unscheduled Flow What direction for the Future Unscheduled Flow What direction for the Future? Question for WECC members at the MIC Meeting June 15, 2007 David Lemmons, UFAS Liaison

Current Unscheduled Flow Mitigation Plan & Procedure Starts with phase shifters (PST) Follows with schedule curtailments During curtailment, responsible entities have choice of action: Curtail schedule that has TDF greater than 5% Create schedule that has a TDF lower than -5% Redispatch generation to provide relief

Current Unscheduled Flow Mitigation Plan & Procedure Paths with Unscheduled Flow history are Qualified via prescribed process Effects of every schedule from any zone to any other zone in WECC has a Transmission Distribution Factor (TDF). The set of TDF values is calculated on a seasonal basis The Qualified Path Operator calls for relief when loading meets criteria

Current UFMP Issues Transmission product is not factored into the relief requirement: no diff F vs. NF Should reliability issues be handled by reliability side entities or PSEs? Disparity between pre-existing and restricted (new) transactions. Should they be equalized? Plan is normally used on 7 of approximately 70 rated paths, should others be allowed? Contract issues related to failure to perform: PSEs could be charged liquidated damages for schedules they curtail outside contract allowances System model is intact only, no outage effects

UFMP Issues (cont.) FERC painted the Eastern Interconnection schedule curtailment (TLR) as ineffective, applauded the Phase Shifter component of WECC UFRP, but said NOTHING about schedule curtailment in the west !?! If someone other than PSE controls Procedure, PSE option$ likely go away. NERC Standards require Reliability Coordinator to initiate/control procedure (IRO-006-3), not how WECC currently does this. Current distributed responsibility to PSE community has many entities spending much time on UF management, training, compliance, etc. Would this be made more efficient if centralized?

Compliance History Previously, under RMS, the receiving entity was responsible for curtailment. Currently, The Version Zero UF Standard submitted under Tier 1 keeps that responsibility with the receiving entity. However, each responsible entity gets to choose which schedules to keep, as the requirement is only to “provide relief”, not to curtail specific schedules.

Current Standard Situation UF Version 0 has been submitted (part of Tier 1 package). Keeps responsibility with receiver. Version 1 (V1) has been completed and is ready to post for process. V1 is essentially the same with some clarification for the dc ties. The UF Plan itself is in need of rewriting. There are many appendices and several areas that do not immediately provide clarity. Future direction has huge impact

Improvements? Expand the Plan to be useful for more/all Paths ? Perform curtailments in order of transmission priority ? Study pre-existing and restricted (new) transactions for effects of equalizing ? Couple real-time outage information to system model in webSAS? Make schedule curtailment effective time to be “now”, not top of next hour?

Improvements? RC’s initiate/control procedure per IRO-006 and have a machine do the curtailment. The Eastern Interconnection does this. Relief is provided but there is no choice in which schedules get curtailed. However, there is no sanction on the receiver for failure to curtail.

The Good & the Bad Decrease workload for PSE/LSE entities - Good Decrease WECC Staff compliance work - Good Eliminate $ sanctions for Members - Good Decrease UF Training for Members – Good Increase workload on the RC’s – bad Shift costs for UF tool from 73 subscribers to one (WECC) or two (RC’s) – bad? PSE/LSEs lose choice of which schedule to curtail (often economic) – bad Does the Good outweigh the bad?

Crossroads ahead This is a Member choice So, in order to plan for the future, UFAS asks for your opinion

Today’s Straw Poll Keep responsibility (and sanctions) for UF curtailment with PSE/LSE (but they retain choice of action and the sanctions) OR Transfer responsibility for UF curtailment to the RC’s, (but give up choice of action and sanctions)