Mgr. Interconnection Reliability Initiatives ECC Update Peak RC Users Group May 3, 2018 Jeremy West Mgr. Interconnection Reliability Initiatives

Peak’s Initiatives Improved Reliability ECC implementation along with SOL changes collectively provided improvements and value Peak led SOL Methodology changes Change in SOL definition Retirement of TOP-007-WECC-1 Provided Path Operators more flexibility in calling for Qualified Path relief Pre-contingency Post-contingency When relief needed, ECC’s real-time data provides accurate relief obligations Main point – we can’t claim that ECC by itself has created all of the value. The ECC is a tool that provides solutions when an SOL exceedance occurs, and the rules (ie standards) associated with SOLs have evolved (with Peak’s leadership)

USF Step 3 and 4 Events April compares SOL methodology July compares tool change Marie recommended explaining the big spike in June 2017 (weather driven, system conditions, etc) As we discussed, we’ve analyzed the spike in the number of USF events in June 2017. There were 66 Step 3 events and 128 Step 4 events in that month for a total of 194 events, compared to around 50 total events for nearby months in 2017. There were 7 Step 3 events and 68 Step 4 events between June 15th and 18th.   For outages, there were ongoing Path 66 outages on the Malin-Round Mountain #2 500 kV and the Round Mountain-Table Mountain #2 500 kV lines which started in April and had an ETR of 6/22/17, and the Grizzly-Malin #2 500 kV line was OOS from 6/5 to 6/18. There were also multiple days with very high temperatures and loading as well as significant phase shifter movements in mid-June according to the RC notes.

Unscheduled Flow (USF) Step 4 Events Number of USF Days per Path Path 30 Path 31 Path 36 Path 66 ECC 14 5 10 13 webSAS 22 8 40 27 Average Step 4 Duration (Hrs) per Path Path 30 Path 31 Path 36 Path 66 ECC 3.0 2.0 3.7 2.2 webSAS 2.5 4.9 4.3 Illustrative period between July to April (2016/17 webSAS, 2017/18 ECC) *Does not include statistics for competing path events

WIUFMP in webSAS vs ECC Focus on Path 30 and Path 66

WIUFMP in webSAS vs ECC Primary benefits from ECC driving WIUFMP events: Factors more accurate for current system conditions Reflect actual relief obtained from Step 4 curtailments rather than proxy value from planning case

ECC Value Proposition Moving Forward To date ECC has provided: Situational awareness on exceedances More accurate support for WIUFMP As paradigm changes in West, ECC will provide value to mitigate exceedances in a coordinated fashion Markets Multiple RCs Currently discussing how to shape the final state of the tool to serve as that primary mechanism for SOL exceedance management between markets and RCs

What does it mean for ECC to be Shared? RC Transitional Plan discusses ECC future Shared tool – cost and support divided Envisions cost allocation to both RCs and BAs Discussions with potential RCs occurring ECC Final State will serve as seams management between RCs Example: IDC in East Discussion amongst potential RCs has indicated support for ECC to serve this role

ECC Final State Phase Peak has been actively working with ECC Task Force on final state since fall 2017 Posted final state white papers Nov. 23 with 30 day comment period Posted white paper revision and response to comments Feb. 22

ECC Final State Phase Serves as guiding “roadmap” for design Business rules straddle policy and design Does NOT serve as detailed design requirements Peak will work with OATI and ECCTF to translate and cover technical design needs

ECC Final State Phase ECC Element experiences SOL exceedance PTDF = pre-contingent OTDF = post-contingent ECC assigns relief obligation to entities with Impact Layer flow above Impact Threshold BAs / TOPs have choice on how to provide assigned Relief Obligation ECC tracks that relief is provided ECC reassesses whether relief will be needed going forward

ECC Final State Phase Identify Impact Layer Components >= Impact Threshold 10% Factor as default E-Tags, Dynamic Transfers, ACE, GTL Use 15-bucket methodology to order components ACE = Zero Off-Element 7 Firm collapsed for all e-Tags and GTL Assign Relief Obligation to BAs Go as deep in buckets to obtain relief

ECC Final State Phase BAs and TOPs would have choice on how to provide relief Relief Obligation assigned based on 2-NH e-Tag BA prefers to preserve e-Tag flow and move native generator To keep relief response timely, ECC will need a deadline for choice

ECC Final State Phase ECC would track response by entities Improvement over just verifying curtailments Verifies that ECC Element flow is decreasing RCs and/or initiating TOPs could increase, decrease, or terminate Element relief request

ECC Final State Phase Key Project Activities Post Final White Paper version week of May 7 Work with ECCTF and OATI on outstanding technical needs Complete Requirements document beginning of Q4 so OATI begins design effort

Upcoming ECCTF Meetings June 11th – 12th ColumbiaGrid Office Portland, OR July 30th – 31st Xcel Office Denver, CO

Thank you! https://www.integrity.oati.com ECC@peakrc.com Jeremy West jwest@peakrc.com (970) 613-3542