RPCG 2026 CCTA Results and Next Steps Colby

RPCG – 2026 CCTA Results and Next Steps Colby Johnson & Vijay Satyal W E S T E R N E L E C T R C I T Y O U N C I C L O O R D I N A T I N G

2 RPCG process • Every 2 year effort • Prior webinars- June, October • Focus of this webinar- Discuss voting results to WECC proposed “include” and “exclude” list • Future meeting/webinar to discuss adjustments W E S T E R N E L E C T R C I T Y O U N C I C L O O R D I N A T I N G

2026 CCTA Results Colby Johnson, Associate Engineer W E S T E R N E L E C T R C I T Y O U N C I C L O O R D I N A T I N G

4 Overview • CCTA Selection Process Review – CCTA Criteria Flow Chart • Transmission Projects: Under Construction – Met Criteria 1 &2: Default Inclusion • Ballot Review: Inclusion/Exclusion List • Transmission Projects: Not Under Construction – Did meet Criteria 3 & 4 & 5 (if necessary) -> Inclusion – Did not meet Criteria 3, 4, 5 -> Exclusion • Polling Tie Projects: Include/Exclude? • Final 2026 CCTA Project List • Future Improvements W E S T E R N E L E C T R C I T Y O U N C I C L O O R D I N A T I N G

5 CCTA Selection Process Review 2026 CCTA Inclusions All Prior CCTA Projects Under Constr. 2026 CCTA Criteria Not Under Constr. Newly-Submitted CCTA Projects W E S T E R 2026 CCTA Exclusions N E L E C T R C I T Y O U N C I C L O O R D I N A T I N G

6 Criteria 1 Project A Project … Project Z No Regional Significance Yes Criteria 2 Yes Criteria 3 No Under Construction No Financial Indicators Yes Criteria 4 Yes Passed RPCG Screen N/A Criteria 5 E No Dependency Check Yes CCTA W No Implement. Indicators S T E R N E L E C T R C I T Y O U N C I Not CCTA C L O O R D I N A T I N G

7 Transmission Projects: Under Construction • These Projects Met Criteria 1 & 2; Included in CCTA Central Ferry – Lower Monumental - Complete and In-Service Delaney-Palo Verde 500 k. V Line Delaney-Sun Valley 500 k. V Line Desert Basin - Pinal Central - Complete and In-Service Devers - Colorado River 500 k. V (DCR) Transmission Line Project - Complete and In-Service Energy Gateway Transmission Project - Segment G (Sigurd - Red Butte 345 k. V line) - Complete and In-Service Hassayampa - North Gila 500 k. V #2 line - Complete and In-Service Interior to Lower Mainland Transmission (ILM) Project Pinal Central-Tortolita - Complete and In-Service Pinal West-Pinal Central-Browning (SEV) - Complete and In-Service West of Mc. Nary Reinforcement Project Group 2 (Big Eddy - Knight) – – – W E S T E R N E L E C T R C I T Y O U N C I C L O O R D I N A T I N G

8 Ballot Results Neutral votes not counted In instance of a “tie”, this group to determine W E S T E R N E L E C T R C I T Y O U N C I C L O O R D I N A T I N G

9 Transmission Projects: Not Under Construction Poll Majority – Agree to Include • Met CCTA selection Criterion 3, 4, and/or 5 (when applicable): – Boardman-Hemingway 500 k. V (B 2 H) – Delaney - Colorado River 500 k. V Transmission Project (Ten West Link) – Energy Gateway: Wallula – Mc. Nary (230 k. V) – Energy Gateway South: Aeolus-Mona (500 k. V) – Energy Gateway West: Bridger – Populus – Energy Gateway West: Windstar to Jim Bridger – Energy Gateway West: Midpoint – Hemingway – Energy Gateway West: Populus – Midpoint – Energy Gateway West: Populus – Cedar Hill - Hemingway – Centennial II: Harry Allen - Eldorado 500 k. V Transmission Project – I-5 Corridor Reinforcement Project (Castle Rock - Troutdale) – Morgan-Sun Valley 500 k. V Line – *Path 8 Upgrade/Colstrip Transmission Upgrade – *Pawnee-Daniels Park *Updates provided after poll sent out; 2 additional “Inclusions” W E S T E R N E L E C T R C I T Y O U N C I C L O O R D I N A T I N G

10 Transmission Projects: Not Under Construction Poll Majority – Agree to “Exclude” Did not meet Criteria 3, 4, and/or 5: Bighorn-Eldorado Centennial West Clean Line Chinook Centennial II (Amargosa-Northwest) Centennial II (Northwest - Harry Allen) Great Basin HVDC Harcuvar Transmission Project Hemingway-Captain Jack 500 k. V Transmission Line Juan de Fuca HVDC Sea Cable Juan de Fuca II HVDC Cable Lamar-Vilas Lassen 230 k. V East/West Tie Lucky Corridor Transmission Project – – – – W E S T E R N E L E C T R C I T Y O U N C I – – – – C L Mountain States Transmission Intertie (MSTI) (Townsend-Midpoint 500 k. V) North Gila - Imperial Valley #2 Project NV Energy Robinson - Harry Allen 500 k. V Line Southern Nevada Intertie Project (SNIP) Southwest Intertie Project - North (SWIPNorth) Sun. Zia Southwest Transmission Project Trans. West Express Transmission Project West Side Tie Tres Amigas Western Spirit Clean Line Westside Tie 345/500 k. V Wyoming-Colorado Intertie Project Zephyr WECC - Eastern Interconnect DC Tie Upgrade Project O O R D I N A T I N G

11 Polling Tie Projects (1 to 1 Include/Exclude) • What is the will of the group, Include or Exclude? • Projects were originally in the “Include” list – Southline Transmission Project (Afton-Apache) • Comment: Project sponsor agrees this should not be included at this time – Southline Transmission Project (Apache-Saguaro) • Comment: Project sponsor agrees this should not be included at this time – Talega-Escondido / Valley-Serrano 500 k. V Interconnect • Comment: Project does not appear in CAISO transmission plan, and has not been submitted to CAISO as a “Merchant Project” Current status – Undecided – and seek input from RPCG • W E S T E R N E L E C T R C I T Y O U N C I C L O O R D I N A T I N G

12 Final 2026 CCTA Project List • • • • Central Ferry – Lower Monumental Delaney-Palo Verde 500 k. V Line Delaney-Sun Valley 500 k. V Line Desert Basin - Pinal Central Devers - Colorado River 500 k. V (DCR) Energy Gateway Transmission Project Segment G (Sigurd - Red Butte 345 k. V line) Hassayampa - North Gila 500 k. V #2 line Interior to Lower Mainland Transmission (ILM) Pinal Central-Tortolita Pinal West-Pinal Central-Browning (SEV) West of Mc. Nary Reinforcement Project Group 2 (Big Eddy - Knight) Boardman-Hemingway 500 k. V (B 2 H) Delaney - Colorado River 500 k. V Transmission Project (Ten West Link) Energy Gateway South: Aeolus-Mona 500 k. V Blue text denotes under construction or in-service • • • Energy Gateway West: Bridger – Populus Energy Gateway West: Windstar to Jim Bridger Energy Gateway West: Midpoint – Hemingway Energy Gateway West: Populus – Midpoint Energy Gateway West: Populus – Cedar Hill – Hemingway Energy Gateway: Wallula – Mc. Nary 230 k. V Centennial II: Harry Allen - Eldorado 500 k. V I-5 Corridor Reinforcement Project (Castle Rock - Troutdale) Morgan-Sun Valley 500 k. V Line Path 8 Upgrade/Colstrip Transmission Upgrade Pawnee-Daniels Park

13 Overall Feedback on Process • Criterion 3 and 4 to be reviewed and/or refined in future planning cycles – Definitions – Thresholds • Adjustments to “criteria” ? – FERC Order 1000 planning based improvements? – Other regulatory/state planning/policy drivers? • Future meeting – June/July – modify CCTA 2028 process? ! W E S T E R N E L E C T R C I T Y O U N C I C L O O R D I N A T I N G

14 Contact Information Colby Johnson System Adequacy Planning Office: (801)819 -7662 cjohnson@wecc. biz Vijay Satyal – Staff Liaison Sr. Policy Analyst vsatyal@wecc. biz W E S T E R N E L E C T R C I T Y O U N C I C L O O R D I N A T I N G