MISO is transforming how it plans for and manages the grid of the future. Given the complex changes underway, Long Range Transmission Planning (LRTP) helps in this effort by developing regional projects to ensure the transmission system is reliable, economic, and compliant for the next 20 years and beyond.
MISO’s Long-Range Transmission Plan (LRTP), an integral part of the MISO Transmission Expansion Plan (MTEP), focuses on developing regional transmission solutions. The resulting Multi-Value Projects (MVPs) are designed to enhance the reliability and efficiency of the grid, ensuring it is positioned to meet future resource developments. Planning is based upon utility and state goals and policies, projected conditions, and industry trends. While LRTP portfolios are not intended to resolve all issues related to the precise siting of future generation or load, they address broader, systemic challenges. Given the scale of these needs, LRTP is implemented in structured phases, or “tranches.” The phased approach includes:
- Tranche 1: Approved in 2022, this phase addresses transmssion needs within the MISO Midwest subregion.
- Tranche 2: This phase continues the focus on MISO's Midwest subregion and is divided into two parts.
- Tranche 2.1 - Approved December, 2024.
- Tranche 2.2
- Tranche 3: Focuses on transmission needs within the MISO South subregion.
- Tranche 4: This phase will focus on addressing challenges along the North/South interface.
LRTP will continue following the 2025 update to MISO’s Future Planning Scenarios which ensure alignment with the latest forecasts and planning conditions. The specific timing for later phases will be determined as the planning process advances.
By proactively planning for long-term reliability, MISO remains committed to delivering a robust and adaptable transmission system capable of supporting a sustainable and efficient energy future.
Approved in December 2024 by the MISO Board of Directors, Tranche 2.1 is the second phase of LRTP and builds on the foundation of Tranche 1.
Tranche 2.1 develops a 3,631-mile 765 kV backbone that ensures future reliability while providing benefits that exceed costs. It includes a $21.8 billion investment for 24 projects and 323 facilities across the MISO Midwest subregion. Projects are targeted to go in service from 2032 to 2034. Highlights include the following:
- Significant step toward enabling future generation as envisioned by MISO’s members, utilities and states in Future 2A.
- Provides a 765 kV backbone, which can carry more electricity, minimize land use reduce energy losses while maintaining high reliability
- Primarily a reliability-based portfolio, but also provides a broad range of value with a benefit-cost ratio ranging from 1.8 to 3.5
Approved in July 2022 as part of MTEP21, the $10.3 billion Tranche 1 portfolio consists of 18 projects that provide spread across the MISO Midwest subregion.
- Provides a foundation for future tranches.
- Addresses issues based on the resource expansion envisioned in Future 1.
- A wide range of value is provided by the portfolio with a benefit-to-cost ratio of 2.6 - 3.8.
- Maximizes the use of existing rights-of-way.
As of December 2024, most projects are well into regulatory approval processes. MISO will monitor the status of these projects through the build phase.