The MISO LRTP meeting held on September 24, 2024, covered detailed updates and analyses regarding the Tranche 2.1 portfolio of projects, focusing on both reliability and economic factors. The meeting started with technical difficulties, but soon transitioned into a comprehensive discussion of the LRTP (Long Range Transmission Plan) process, specifically the final stages of the Tranche 2.1 projects.
Overview and Timeline: The meeting began with a presentation on the journey through Tranche 2.1, emphasizing the collaboration between stakeholders and the internal efforts by MISO staff, totaling over 40,000 hours of work. The process followed MISO’s seven-step framework, which is designed to align with member and state goals across the footprint while addressing key reliability and economic needs through regional least-regrets transmission. The team highlighted that the process has been iterative and robust, involving hundreds of participants and constructive feedback, which shaped the final project proposals.
The portfolio was developed with a focus on future energy needs, including both regional and local transmission issues. The goal was to ensure that the system could handle the massive transfers expected under future scenarios and the increased load levels anticipated.
Reliability and Economic Models: The presenters explained that MISO used various reliability and economic models to assess the transmission system under different resource evolutions and load levels. They shared results showing that the system would need significant enhancements to manage these future requirements. The system’s transfers, especially under future scenarios, would be much larger than those seen today, with average future transfers comparable to today’s high-transfer cases.
Feedback and Refinement: During the presentation, the team acknowledged the feedback received from stakeholders. For instance, stakeholders requested the study to explore the possibility of larger portfolios, leading to the addition of seven new projects and the replacement of another. While not all projects submitted were included in the final portfolio, MISO identified several as potential future considerations, especially those that had local or smaller-scale relevance.
Cost and Project Groupings: The portfolio’s cost was finalized at $21.8 billion, and it was divided into 24 projects. The projects were grouped based on electrical and geographic proximity, as well as voltage levels. The project numbering began at 19 (to align with the numbering of Tranche 1 projects), and the service dates were staggered, with 345 kV facilities expected to be operational by 2032 and 765 kV facilities phased in from 2033 to 2034. The aim was to get the entire portfolio operational within ten years, with an emphasis on building a strong 345 kV foundation before transitioning to the more complex 765 kV facilities.
Key Results: The reliability and economic deep dive revealed that the portfolio significantly reduces thermal and voltage severity across multiple models, with improvements seen in thermal severity indices (e.g., 68% reduction in the 2042 average model). The system showed enhanced flexibility in handling different transfer scenarios, including East-to-West and Lower-to-Upper transfers, and a low renewable output scenario during winter. Notably, the portfolio resolved 90% of voltage violations below 200 kV and 70% above 200 kV.
Economic Analysis: The economic portion of the presentation, led by Clayton Mayfield, discussed how MISO assessed the portfolio’s economic impact. The key metrics were curtailment relief, load LMP (locational marginal pricing) reduction, and congestion relief. The portfolio was found to provide 27.1 million megawatt-hours of curtailment relief, with significant reductions in the West region. The reduction in LMP across MISO Midwest helped facilitate the use of more economical resources, and congestion relief was seen at nearly 30%, with substantial reductions across all regions.
Stakeholder Questions and Comments: Throughout the meeting, stakeholders posed questions regarding specific details, such as the breakdown of project costs and the process for identifying competitive and non-competitive upgrades. There were also questions about the in-service dates and potential reimbursement opportunities for upgrades tied to the projects. MISO clarified that many of these details would be addressed in future meetings.
The meeting concluded with MISO reiterating the robustness of the Tranche 2.1 portfolio, noting that it would enable reliable transfers across the system, ensure future resource adequacy, and provide significant economic benefits. MISO indicated that formal feedback on the draft report would be collected, and the final approval process was scheduled for October.
