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
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.
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
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