The complex challenges to the electric system that are being addressed by MISO’s Reliability Imperative have been steadily materializing throughout the U.S. and within the MISO region in recent years. The challenges are driven by a combination of economic, technological, policy-related and extreme weather factors that are explained in MISO’s Reliability Imperative Report. Widespread retirements of dispatchable resources, large spot load additions from new data centers and the reshoring of manufacturing, more frequent and severe weather events, increased reliance on weather-dependent renewables and other factors have altered the region’s historic risk profile, creating risks in non-summer months and other times that rarely posed challenges in the past.
MISO is transforming how it plans for and manages the grid of the future, given all of these complex changes. Long Range Transmission Planning (LRTP) develops backbone regional projects to ensure transmission is reliable, economic and compliant in the future, given state and utility policy and goals, projected conditions and industry trends. All of this is accomplished while demonstrating the portfolio provides benefits in excess of costs, and value that is consistent with MISO’s Tariff criteria. LRTP tackles needs and issues that are not easily addressed in cyclical planning processes like MISO’s MTEP which focuses on more local and near-term needs. And, it looks at a long-term (roughly 20-year) view of the system to address future issues while also guiding near-term transmission planning.
MISO’s Approach to Long Range Transmission Planning
The overall LRTP planning effort is large and complex — unlike any effort MISO or any other organization has undertaken in the history of the U.S. grid. It takes a long time to plan for large regional solutions, especially when managing against a great deal of uncertainty. LRTP is also costly as investing in all identified issues could require an investment of at least $50 billion. Additionally, LRTP has to be conducted as rapid evolution continues through business plans, state energy/environmental policies and other dynamic factors that keep impacting the region’s transmission needs.
The need for LRTP is urgent, given these changes. MISO works carefully with stakeholders to develop least regrets, robust portfolios while balancing the need for speed. To address the complexity and magnitude of work, MISO is planning in more manageable phases called tranches. The $10.3 billion Tranche 1 portfolio addressed the needs in the MISO Midwest Subregion and Tranche 2.1, estimated at $21.8 billion, continues to focus on this area. It is scheduled to be presented to MISO’s Board of Directors for an anticipated December 2024 approval. Tranche 2.2 will develop more solutions to issues in the Midwest that were out of scope for Tranche 2.1. In Tranche 3, MISO will shift to the needs in its South Subregion, followed by Tranche 4 which will study transmission needed to connect the north and south.
Learn more about LRTP in a recent overview of the journey to develop Tranche 2.1 and in the Tranche 1 report.