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MTEP21 Report

We began the 2021 MISO Transmission Expansion Planning (MTEP21) in 2020 when stakeholders first submitted proposed transmission projects.  MISO engineers and stakeholders continue to evaluate transmission issues and each proposed solution to determine whether the project is appropriate for inclusion in MTEP.

Transmission studies, featuring robust reliability and economic analyses, help MISO members make prudent planning and investment decisions to continue delivering reliable, least-cost energy.  Reliability projects, including age and condition upgrades, a vital part of MTEP planning, account for the majority of all recommended projects.

MISO's Board of Directors approved the MTEP21 Executive Report and Appendix A during its December 2021 meeting.  Final MTEP21 documents are offered below.

An addendum to the MTEP21 Report will be presented to the Board of Directors for approval in July 2022.

Fleet landscape requires enough capacity be available to meet the needs of all consumers in the MISO footprint to meet peak load serving needs.  To achieve this, MISO supports its states and load-serving entities by providing projected risks and continuously works to improve transparency into near and long-term requirements.

A convergence of trends, including an aging generation fleet and growth of variable energy resources, has required MISO to look at existing processes to support states' and load-serving entities' efforts to satisfy their fleet landscape requirements.  Improvements in MISO processes will benefit the system through ensuring sufficient energy is able to meet operations needs in all times of the year.


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MISO's generation fleet continues to evolve, and MISO is studying the impacts of increasing levels of renewable resources on the system. MISO also continues to follow federal and state policy as well as monitor industry trends. Additionally, interregional planning is critical to maximize the overall value of the transmission system and deliver savings for customers. 

Interregional studies conducted jointly with MISO's neighboring planning regions are based on an annual review of transmission issues at the seams. Depending on the outcome of those reviews, studies are scoped out and performed.  


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The MISO footprint is not a monolithic area, but a dynamic region made up of different geographies, different generation mixes, varied pricing and conditions that affect load. With its 50 Transmission Owner members, MISO has more than $37.9 billion in transmission assets under its functional control. This section presents additional regional energy information to show a more complete picture of the regional energy system.


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The complete results of MTEP21 reliability assessments are detailed in confidential appendices D3 through D10 and will be available by December 31st on the MISO ShareFile site at https://misoenergy.sharefile.com/, subject to Critical Energy Infrastructure Information and non-disclosure agreements.  These results serve as compliance evidence for a variety of NERC planning standards listed on the MISO public website at http://www.misoenergy.org/planning/transmission-planning/reliability-planning 


MISO introduced the Long-Range Transmission Planning (LRTP) initiative to stakeholders in August 2020 to begin exploring the study requirements for development of a regional transmission plan that addresses future challenges of the resource fleet evolution. The LRTP initiative is MISO’s response to the current and future resource evolution that has and continues to affect the bulk electric system. The scale and pace of these changes require prompt attention to develop the most efficient, cost-effective investments that will ensure grid reliability in the future. 

The LRTP work has built off the earlier work on the Renewable Integration Impact Assessment which showed the need for transmission investment to address the concerns around the extensive growth in renewable resources and increasing regional transfers driven by variability of the renewable output. 

MISO believes it is important to move quickly, while ensuring a least regrets plan.  Meeting both objectives is critical to enable our member plans, and to ensure reliable power delivery for customers with investment decisions that appropriately balance resource and transmission solutions on a regional scale to ensure the best cost outcomes for customers. 

As an amendment to MTEP21, Tranche 1 projects were developed to address the needs identified in Future 1 for the Midwest subregion under a range of system conditions.  In addition, the benefits analysis quantified the overall value provided by the Tranche 1 portfolio across several categories of reliability and economic benefits. 


MTEP21 LRTP Tranche 1 Executive Summary

MTEP21 Addendum-LRTP Tranche 1 Portfolio Report

MTEP21 LRTP Addendum Appendix A

MTEP21 LRTP Tranche 1 Appendix A-4 Indicative Cost Allocation

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