Photo 27947817 © Jessica Kirsh |

MISO Unveils Draft Proposal for the Next Phase in Major Transmission Build

March 5, 2024
Long Range Transmission Plan Tranche 2 map and details released.

After extensive stakeholder engagement, MISO is sharing an initial, draft proposal for a set of Tranche 2 transmission solutions. This is the second phase of the grid operator’s Long Range Transmission Planning (LRTP) effort and builds on the investment in Tranche 1 through defining a set of new projects in its Midwest Subregion. 

“This portfolio focuses on creating a regional backbone to meet the long-term needs of our region,” said Aubrey Johnson, vice president of system planning at MISO. “Our transmission solutions – creating a sort of interstate highway system for electricity – enable the future resource plans of our states, utilities and members by addressing regional needs, while recognizing that local issues will continue to be addressed through our MTEP and Generator Interconnection Queue processes.”

The Tranche 2 portfolio is the next step toward developing a system needed to reliably and efficiently meet the load growth and resource evolution described in MISO’s members’ plans. With an anticipated cost between $17 billion to $23 billion, Tranche 2 expands on members’ investment by developing a set of transmission solutions to support the next evolution of the system. Because of the impact of increasing load growth and the changing resource mix, the current potential Tranche 2 portfolio features 765 kV lines which enable long-term value based on distance, cost and land use. They also reduce right-of-way permitting needs required in regulatory approval processes and help address environmental concerns.

“The future grid must be able to integrate new load growth and respond to extreme weather, and a robust transmission system is required to ensure this occurs reliably and efficiently,” added Laura Rauch, executive director of transmission planning at MISO. “We know further transmission development can provide value and we will continue working with our stakeholders to refine this portfolio and ensure it is sufficiently robust.”

MISO has more work to refine the portfolio, ensure robustness and demonstrate benefits in excess of costs and consistent with its Tariff criteria. Stakeholders have the opportunity to provide alternatives to improve or enhance the concepts outlined in this portfolio and provide additional feedback through LRTP workshops which are fundamental to MISO’s comprehensive planning process.  Balancing the need for urgency while developing least-regrets solutions, MISO anticipates recommending the final portfolio to the Board of Directors later this year.

LRTP is a key component of the Transmission Evolution pillar of MISO’s Response to the Imperative — the shared responsibility that states, utilities, members, and MISO have to address the complex challenges driven by generation fleet change and extreme weather events increasingly threatening electric reliability in the region. Visit the MISO website for details on the draft proposal. 

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