RPG Meeting Meeting Summary – 08/13/24

1 – Antitrust Admonition

2 – Miscellaneous Updates – ERCOT

3 – High Level Overview of Argonne National Lab ANL Study on Potential Severe Weather Event Scenarios – Leah Talabel

• Presentation began with a brief intro on Argonne National Lab’s (ANL) new tool introduced in 2019 for estimating impacts on transmission facilities from severe weather events (e.g., hurricanes).
• ERCOT engaged ANL again in 2023 due to increased interest in severe weather impacts, focusing on historical and hypothetical major hurricanes’ effects on the ERCOT grid.
• Overview of ANL: Part of the Department of Energy lab network, performs work for DOE, Homeland Security, and private sectors, emphasizing applied science in energy resiliency.
• Details of ANL’s HEADOUT tool used for the study, which estimates damage to generators, transmission lines, substations, and customer impact from hurricanes.
• Study scenarios included three hypothetical worst-case (Category 5) hurricanes impacting Houston, Corpus Christi, and the Rio Grande Valley, and evaluation of nine historical storms.
• Model evaluation and updates based on real-time and projected hurricane impacts, validated through testing of historical hurricanes.
• Results showed varying damage levels (none, minor, moderate, severe) and estimated restoration times for all studied storms.
• ERCOT plans to share study results with Transmission Service Providers (TSP) ERCOT RTP will use study results to conduct biennial grid resiliency studies as directed by 87R-SB1281
• Discussion on the importance of considering multiple events vs. a single event for comprehensive coastal region impact analysis.
• Clarification on the study scope: focusing on the coastal area impacted by hurricanes for this year, with plans to expand to other scenarios and regions in future cycles.
• Explanation on the confidentiality of study results due to Critical Energy Infrastructure Information (CEII), thus limiting detailed sharing to relevant TSPs only.
• Questions and comments from stakeholders regarding the study’s practical impacts: potential system reinforcements, projects to address identified weak spots, and inclusion of broader weather event scenarios in the future.

4 – EIR Status Update – Brownsville Area Improvements Transmission Project – ERCOT – Caleb Holland

• Caleb Holland gave the Brownsville Area Improvement status update
• The AEP Brownsville Area Improvements project was submitted for regional Planning Group review in March 2024.
• The project is estimated to cost $388 million with an estimated in-service date of May 2027.
• It aims to address thermal overloads and voltage violations in the Brownsville area.
• Various project options were discussed and evaluated, including removal of options 4 and 6 due to infeasibility, and introduction of options 7 and 8.
• Modifications were made to options 2 and 5, now referred to as options 2A and 5A, based on N-1-1 maintenance outage analysis.
• Detailed descriptions and evaluations of each option were provided, including specific construction plans and thermal overloads results.
• ERCOT independent review is ongoing, with regular status updates planned for future RPG meetings.
• Cost estimates and feasibility assessments requested from transmission service providers including AEP, Brownsville Public Utilities Board, and Sharyland.
• A congestion analysis may be performed to ensure identified transmission upgrades do not result in new congestion within the study area.
• Stakeholder questions and comments covered feasibility, cost considerations, and impact of proposed options on the transmission system.

5 – EIR Status Update – Canton Area Loop Project – ERCOT – Robert Golan

Robert Golen, ERCOT, presented the update

Background

• Rayburn Electric Cooperative (REC) submitted the Canton Area Loop Project in March 2024.
• Estimated cost: $26.03 million, requiring a CCN.
• Estimated completion date: October 2026.
• Objective: Provide looped service for REC Canton Switchyard, limiting radial loads to less than 20 MW.

Project Scenarios

• Option 1: New 345/138-kV Switchyard tapping into the tricorner to Tyler Grande 345 kV line, upgrading Canton 138 Switchyard to a 3-breaker ring bus configuration.
• Option 2: Similar to Option 1 but tapping into the tricorner to Elkton 345 line.
• Option 3: Construct a new Oncor 138 kV Switchyard with a 3-breaker ring bus configuration at a tap point between Canton (Oncor) and Explorer pipeline tap , upgrading REC Canton 138 to a 3-breaker ring bus, constructing 4.2 miles of 138 kV line.
• Option 4: Expand existing Oncor-owned Canton 138 kV substation, construct 4.2 miles of 138 kV line.

Evaluation Results

• No voltage, thermal, or unsolved power flows issues in planned maintenance evaluation.
• Long term load serving capability assessment:
  • Options 1 & 2: 215 MW
  • Options 3 & 4: 963 MW
• Cost Estimates:
  • Options 1 & 2: $49.33 million each
  • Option 3: $26.03 million
  • Option 4: Deemed infeasible

Selected Option

Option 3

Reason for Selection

• Least cost option ($26.03 million).
• Fully addresses REC planning criteria with no reliability issues.
• Provides better long-term load serving capability.

Final Recommendation

• Construct new Oncor 138 kV Switchyard, tap between Oncor Canton substation to the Explorer pipeline 138 kV line.
• Upgrade Canton 138-kV  to a 3-breaker ring bus.
• Construct new Canton to Oncor Switchyard 4.2 miles 138 kV transmission line with ratings of at least 669 MVA (normal) and 752 MVA (emergency).

ERCOT’s Position

• ERCOT will not endorse the project as it does not meet NERC or ERCOT planning criteria.
• Issue EIR report soon, without endorsement or acceptance letter for PUC filing.

Discussion

Questions

• Brian Hithersay, Brazos Electric Coop: Does ERCOT’s non-endorsement mean opposition to the project, would ERCOT classify this as tier-4 neutral project?
  • Answer: Project maintains tier two classification; ERCOT will not endorse because it doesn’t meet NERC or ERCOT criteria.
• Brian Hithersay, Brazos Electric Coop: Implications for similar projects by Brazos Electric?
  • Answer: Similar evaluations will be performed; no endorsement letters if projects don’t meet criteria.

6 – EIR Status Update – Rand Area Loop Project ERCOT

• Abhishek Penti presented a status update for the REC Rand Area loop project EIR study.
• The project was submitted for review in May 2024, estimated to cost $32.2 million and expected to complete by April 2027.
• The project aims to limit radial load to less than 20 MW and provide looped service to the Rand substation.
• ERCOT’s independent review of the project is underway.
• Six options were evaluated for the project, with options 3, 4, 5, and 6 selected for further evaluation.
• Options 1 and 2 showed thermal overload issues.
• Option 3 is the preferred option by Rayburn Electric Cooperative.
• Further analysis will include maintenance, outage, long-term load serving capability, cost estimates, feasibility assessments, and congestion analysis.
• Final recommendation is expected by the third quarter of 2024.
• A query was raised about tying the project with the Canton loop project due to their proximity, but it was noted that differing service dates and economic justification resulted in them being addressed separately.

7 – Connell 345/138-kV Switch and Connell to Rockhound 345-kV Double-Circuit Line Project Overview Oncor

• Eduardo Camilla from Oncor presented the project overview.
• Load growth in Martin and Middleton counties causing post-contingency low voltages and thermal overloads.
• Identified issues in the Sale Ranch, Tall City 138 kV line, and Rockhound 345 kV autos.
• Project includes 9.2 miles of 138 kV transmission line rebuild and 13 miles of greenfield double circuit 345 kV line from Rockhound to Connell.
• Construction of one new 345/138 kV switching station (Connell Switch ) with two new 600 MVA autos.
• Estimated project cost is $110 million (Tier one RPG submittal).
• Diagram overview: pre-project and post-project states clarify voltage support and load rebalancing.
• Requires a CCN for the 13 miles of greenfield 345 kV double circuit line from Connell to Rockhound.
• Construction expected to begin in 2025, with an anticipated completion date around 2027.
• RPG review completed on July 10, and ERCOT independent review expected by December 7.

8 – Venus Switch to Sam Switch 345-kV Line Project Overview Oncor – Zahra Jianpanah

• Zahra Jianpanah from Oncor presented an overview for the RPG, including the rebuild of the 345 kV double circuit line from Venus Switch in Ellis county to Sam Switch in Hill county.
• Existing line rating is 1072 MVA with an estimated rebuild cost of $118.9 million.
• Project justified due to thermal violation under NERC P1.2 and NERC P2.1 contingencies, with observed line overloading at 117%.
• Proposed rebuild includes a conductor capable of 5000 amps, but limiting elements at Venus (3200 amps) and Sam (3000 amps) will limit the effective capacity to 1792 MVA and 1912 MVA.
• No current need identified to rebuild switching stations at Venus and Sam, though future upgrades may be proposed based on system reliability assessments.
• Discussion on whether the current and future anticipated loads have been accounted for – confirmation given that they have.
• Clarification that despite 5000-amp capability, terminal equipment upgrades are deferred due to existing breaker and bus limitations.
• Lone Star’s perspective shared: some equipment at Sam Switch (like wave traps) needs upgrades for full 5000-amp capability.
• Consideration of potential structural changes required due to the heavier quad bundle conductor.
• Solar Proponent inquired about future interconnection requests: new 345-kV substations will accommodate 5000 amps.

9 – ERCOT Independent Review Scope Venus Switch to Sam Switch 345-kV Line Project ERCOT

• Presentation given by Sarah Gunasekera
• Oncor submitted the Venus Switch to Sam Switch 345 kV line project to RPG in June.
• The project is classified as tier one with an estimated cost of $118.9 million, aimed for completion in May 2026, and won’t require a CCN.
• Project addresses post-contingency thermal overloads on the double circuit 345 kV line.
• ERCOT is independently reviewing the project.
• Oncor’s proposal involves rebuilding existing lines with higher ratings over approximately 38 miles.
• ERCOT’s study will focus on north and north-central weather zones, especially Ellis and Hill counties.
• 2023 RTP summer peak case will be used, with updates from TIP report and other projects’ service dates prior to May 2026.
• Generation and load will be updated consistent with 2023 RTP guidelines.
• Studies will assess contingencies, thermal violations, voltage deviations, project alternatives, maintenance outages, loading capabilities, and more.
• Final recommendations expected in Q4 of this year.
• ERCOT plans to use 2023 cases until 2024 cases are fully vetted at the end of the year. Some updates to study area match the latest data.

10 – 2024 Long-Term System Assessment LTSA High Large Load Adoption Scenario ERCOT

• Presentation of the 2024 LTSA update, focusing on a high large load adoption scenario.
• Study examines the potential impacts of large loads on reliability and economic requirements.
• Scenario uses 2013 weather year with different assumptions for current trends and high load growth projected by TSPs.
• Comparison between current trend and high large load adoption scenario includes peak load, capacity mix, and retirements by 2039.
• High load growth leads to increased gas CT, battery, and solar capacity expansions.
• Total net capacity significantly higher in the new scenario (426.1 GW) compared to current trend (209.8 GW).
• Economic model used to calculate market prices, with detailed methodology to be provided in the final LTSA report.
• Discussions on capacity mix changes, peak loads, retirements, and price calculations.
• Operational challenges and solution strategies for managing future grid with large solar power and battery installations.
• Cost considerations hindering the economic feasibility of small modular reactors (SMRs).
• Emphasis on transmission planning as the next step in the study process.

11 – 2024 Regional Transmission Plan RTP Economic Study Stability Interface Limits Update ERCOT

• Pengwei Du provided an Update for the 2024 RTP economic study stability interface limits.
• In July meeting, presented stability interface limits for 2024 RTP economic study.
• Created four South Texas export/import GDC limits due to cascading failure risks.
• 2024 RDP economic study for 2026 modeling year includes specific limits:
  • South Texas Export:
    • Pawnee to Spruce: 541 MW
    • Pawnee to Tango: 575 MW
  • South Texas Import:
    • Pawnee to Spruce: 483 MW
    • Katoen to Lonhill: 548 MW
• GTC methodology posted on MIS February 28, based on low priority condition.
• For 2029, studied GTC exit strategy for improvements:
  • San Antonio South Reliability I Project
  • LRGV Transmission Improvement Project
  • San Antonio South Reliability II Project
  • Rebuilding the existing Tango-Goddard-Katoen-Lon Hill 345-kV line to a double circuit with a new rating of at least 1746 MVA.
• 2029 GTC limits found not binding for real-time operations.
• ERCOT will establish South Texas export/import GTC limits for 2029 if necessary.
• Planning horizon for the study includes near-term year 2026 and further term year 2029.
• Limits derived as 85% of the posted MIS limits.
• Discussion on whether Tango to Lonhill rebuild will be an RPG project.
• Rebuild is part of the 2023 RTP placeholder projects, expected to resolve by 2029.
• Separate GTC limits imposed for South Texas import/export and related upgrades.
• Updates on the south to central study affecting the Tango to Lonhill rebuilding.

12 – 2024 Long-Term Load Forecast with Application of New Waterfalls ERCOT

• Initiated by Sam Morrison, updates include contracts and officer letters for load forecasting.
• Team decided to update the long-term load forecast using a new waterfall method.
• Collected data from RTP surveys; added better ramping for more accurate forecasts.
• Scope includes historical weather years, economic drivers from Moody’s analytics, and historical load.
• January 2024 long-term load forecast differs from the current one due to updated factors.

• Key components of the forecast include base economic forecast, rooftop PV, electric vehicles, contracts, and officer letters.
• Waterfall method adds transparency by breaking down forecast growth in layers.
• Highlighted the summer and winter peak demand forecasts, including large flexible load reduction assumptions.
• Explained the process of including contracts and officer letters into the forecast.
• Responded to questions about specific load types, method improvements, and tracking ongoing load requests.

13 – Adjourn