The Midcontinent Independent System Operator (MISO) has released its 2026 Transmission Expansion Plan (MTEP 26), a portfolio totaling nearly $17.3 billion across 562 projects, according to rtoinsider.com. The plan outlines blueprints for 2,449 line miles of new or upgraded infrastructure, marking the most expensive annual transmission portfolio not tied to a long-range strategic plan. Stakeholders reviewed the package during planning meetings in late August and early September, with final board approval scheduled for early December.
What it means
The $17.3 billion total represents a significant increase from MISO’s June projection of approximately $15 billion for the annual portfolio. The cost surge is driven by 81 approved expedited transmission projects added recently, which support 20.3 gigawatts of large load additions—more than double the 9.3 gigawatts supported by MTEP 25. While baseline reliability projects meeting North American Electric Reliability Corporation (NERC) criteria account for nearly $3 billion, slightly more than $13 billion is allocated to “other” projects addressing load growth, aging infrastructure, and local reliability needs. High industry inflation also contributes to the elevated costs.
Louisiana leads MISO states in approved project investment share with $3.85 billion, followed by Wisconsin at almost $2.7 billion, and Arkansas and Michigan each holding slightly more than $2 billion. Entergy Louisiana submitted an estimated $4.5 billion across 32 projects this year, including hundreds of miles of 500-kV lines intended to serve Meta’s Hyperion data center in Richland Parish. Specific major components include a nearly $1.5 billion West Fork Creek-to-St. Landry 500-kV line and switching station project, a $1.1 billion West Fork Creek 500-230-kV substation project, $900 million for El Dorado-to-Smalling 500-kV work, and $270.5 million for Mount-Olive to-Cargas 500-kV line and substation work. Most projects in MTEP 26 are scheduled for service in 2027 and 2028. The MISO Planning Advisory Committee will review the plan in early November, followed by a System Planning Committee vote mid-November and final board approval in early December.
Key facts
- Total cost: $17.3 billion
- Number of projects: 562
- Line miles: 2,449
- Baseline reliability projects: Nearly $3 billion
- “Other” projects (load growth, aging infrastructure): Slightly more than $13 billion
- Approved expedited projects: 81
- Large load additions supported: 20.3 GW (up from 9.3 GW in MTEP 25)
- Louisiana investment share: $3.85 billion
- Wisconsin investment share: Almost $2.7 billion
- Arkansas and Michigan investment shares: Slightly more than $2 billion each
- Entergy Louisiana submissions: Estimated $4.5 billion across 32 projects
- Service timeline: Mostly 2027–2028
Source: rtoinsider.com, reporting MISO’s 2026 Transmission Expansion Plan filing