Enhanced Curtailment Calculator (ECC) Task Force Joint Guidance Committee

1. Enhanced Curtailment Calculator (ECC)Task ForceJoint Guidance Committee Presentation and Motion to the OC & MIC Standing Committee Meetings March 27-29, 2012

2. Enhanced Curtailment Calculator, ECC ECC Task Force Members • OC - Brenda Ambrosi – BC Hydro • OC - Carl Dobbs – WAPA CA • OC - David Lunceford - CAISO • MIC - Raj Hundal – Powerex • MIC - David Lemmons – Xcel (Vice Chair) • MIC - Doug Reese – Tri-State • WECC RC - Linda Perez (Chair) • WECC RC - Jeff Sundvick (acting Chair)

3. ECC Task Force Motion • The MIC and the OC support the investigation into the development of an ECC tool with the following capabilities and associated budget estimate: • The ability to unload overloaded BES elements. • The ability to identify every significant contributor to BES facility or path loading, including contributing schedules and contributing generation. • The ability to be predictive in nature. • The ability to integrate load and generation forecasts into the solutions.

4. ECC Task Force Motion (Cont) • The ability to calculate Power Transfer Distribution Factors (PTDFs) and Outage Transfer Distribution Factors (OTDFs) based on real-time conditions. - The creation and seamless integration with a centralized outage management tool. • The ability to add system elements as needed in real-time for analysis and possible mitigation. • The ability to ensure Transmission Priority is used in conjunction with TDFs for schedule curtailments. • The ability to incorporate sub-hourly schedules.

5. Enhanced Curtailment Calculator, ECC • Objective The ECC project seeks to improve the wide-area view of Reliability Coordinators (RCs) in the Western Interconnection such that they better understand the current operating state of the bulk electric system and are better equipped to assign relief obligations during periods of transmission congestion that are more representative of those actually contributing to the congestion.

6. Enhanced Curtailment Calculator, ECC • Problem Statement The ECC project was initiated in response to WECC members seeking to improve the tools used by the RCs to monitor the operation of the Bulk Electric System and thereby ensure reliability for the interconnection. The area identified as needing improvement is the ability to identify and then take appropriate actions to reduce loading on facilities when the facilities are at or very near their System Operating Limit (SOL).

7. Enhanced Curtailment Calculator, ECC • Problem Statement (cont.) The current congestion tool, webSAS, is only used to calculate curtailment responsibility on six Qualified Transfer Paths. It does not calculate tag curtailments with respect to transmission priority, account for sub-hourly or untagged schedules, determine generation for potential redispatch, or calculate distribution factors based on current system conditions and topology. As increased amounts of variable generation penetrate the interconnection it will be necessary for these calculations to interface with SCADA data to provide reliable analysis in near real-time.

8. Enhanced Curtailment Calculator, ECC • Scope The proposed ECC would calculate impacts on many more paths or distinct elements; potentially all rated paths; and some additional, currently unrated paths. The proposed enhancements would allow real-time updates of transmission system data to include actual generation and outages (currently the data is updated twice annually) and a more granular model of the physical system.

9. Enhanced Curtailment Calculator, ECC • Benefits - Accounts for all tagged and untagged system flows. - Allows for real-time updates of transmission system data to include actual generation and outages. - Facilitates pro forma tariff compliance by transmission providers to perform pro rata curtailment calculations based on transmission and/or generation priority. - Provides greater accuracy and system topology for reliable congestion management decisions by the RC’s and Transmission Operators.

10. Enhanced Curtailment Calculator, ECC • Benefits - Accounts for all tagged and untagged system flows.

11. Enhanced Curtailment Calculator, ECC • Benefits - Allows for real-time updates of transmission system data to include actual generation and outages.

12. Enhanced Curtailment Calculator, ECC • Benefits - Facilitates pro forma tariff compliance by transmission providers to perform pro rata curtailment calculations based on transmission and/or generation priority.

13. Enhanced Curtailment Calculator, ECC • Benefits - Provides greater accuracy and system topology for reliable congestion management decisions by the RC’s and Transmission Operators.

14. Enhanced Curtailment Calculator, ECC • Timeline

15. Enhanced Curtailment Calculator, ECC • WECC process going forward - If the motion is approved by MIC & OC, this estimate will be included in draft Business Plan & Budget presented to the BOD. - If the budget is approved by BOD and includes the ECC, it will then allow us to proceed to RFP. • If the RFP and staff costs are still below budget, no further approvals are necessary to proceed. • If costs exceed the budget estimate significantly, we will need to re-visit the proposal with the BOD and Task Force.

16. Enhanced Curtailment Calculator, ECC • Roles & Responsibilities of BAs, TOPs, and RC

17. Enhanced Curtailment Calculator, ECC • Implementation testing and training

18. Enhanced Curtailment Calculator, ECC • Task Force status evaluation/determination by JGC after completion of deliverables.

19. ECCTF & UFAS Roles • Process to determine which nominated elements can be included in the ECC Tool. (ECCTF) • Process to use the Qualified Devices during a UFMP. (UFAS) - Ability to add elements on the fly. (ECCTF) - Modeling of specific elements (including source/sink points) for TDF calculation. (ECCTF, e.g. continue using seasonal WECC planning model with monthly updates relative to any 100kv or higher element. Or, use WWSM, six-week uploads with real-time updates.)

20. ECCTF & UFAS Roles • Determination of minimum TDF and physical impact thresholds and how they are used for curtailment evaluation. (UFAS is addressing, ECCTF can review) • Impacts, quantification, and treatment of non-tagged system uses. (ECCTF) • Training process for WECC RC and WECC BA on new procedures. (ECCTF) • Process to update and provide real time information on outages and disturbances. (ECCTF)

21. Craig L. Williams WECC Market Interface Manager Cell 801-455-9812 cwilliams@wecc.biz Questions?