The cost estimate for MISO’s 2025 Transmission Expansion Plan (MTEP 25) has fallen slightly from previous estimates to $12.36 billion.
MISO previously clocked MTEP 25 at $13.1 billion and 444 projects, driven by growing load. (See MISO 2025 Transmission Planning Cycle Rises to $13B.) The newest version includes 10 fewer projects.
The RTO said MTEP 25 “is shaping up to be another significant year driven by load growth and reliability.” According to the grid operator, MTEP 25 includes 1,930 miles of transmission lines (44% of which are new) that would accommodate nearly 11.6 GW of spot load additions.
The 2024 MTEP included $6.7 billion worth of projects. That figure does not include the $22 billion second long-range transmission portfolio that technically was included under the annual planning cycle.
MTEP 25 contains $3.44 billion in baseline reliability projects as dictated by NERC standards, $673 million in projects necessary for generator interconnections, nearly $5 billion in projects for load growth, $1.38 billion in projects to address the age and condition of existing facilities, $1.3 billion in projects to satisfy locally defined reliability criteria and $489 million to address more general local needs.
Louisiana is set to receive the most investment this year, at more than $3.4 billion. The amount is split between baseline reliability projects and those needed to meet load growth.
MTEP 25’s 10 most expensive projects account for 44% of the portfolio’s total cost, with four of the 10 in Louisiana. Entergy Louisiana’s Cargas 500-kV station and Smalling 500/230-kV station project in the northern part of the state is the year’s most expensive, at $1.2 billion. Entergy Louisiana said the project is necessary to support new customer load. The work would be located near a proposed Meta data center slated for Richland Parish.
Entergy Louisiana’s Babel-to-Webre 500-kV baseline reliability project takes the second-most expensive slot at almost $1.1 billion.
This year, 49 projects went through MISO’s expedited project review and were cleared to begin construction before MISO’s Board of Directors votes on approving this year’s transmission package in December.
At a Sept. 5 West Subregional Planning Meeting, Joseph Dunn, MISO director of transmission planning, said the “tremendous” number of expedited review requests were brought on by load growth.
MISO’s modeling for MTEP 25 assumes projects from the second long-range transmission portfolio enter the scene on schedule in 2035. Five MISO states — the majority of which won’t contain a project — are trying to revoke the cost-sharing of the $22 billion portfolio, which would put the projects in jeopardy. (See MISO States Split on FERC Complaint to Unwind $22B Long-range Tx Plan.)
This year’s transmission expansion package also contains a blast from the past, as Northern States Power has entered a $92 million maintenance project for a 345-kV line that was part of MISO’s 2011 Multi-Value Project portfolio.
According to MISO, any maintenance on Multi-Value Projects must be classified under the multi-value category.
MISO plans to publicly post its MTEP 25 report Sept. 29, kicking off a two-week comment period for stakeholders. The grid operator will preview a more final MTEP 25 report at the Oct. 8 Planning Advisory Committee meeting.
