MINNEAPOLIS — MISO’s 2025 Transmission Expansion Plan (MTEP 25) has amassed another $2 billion in investment since early spring, bringing its total to $13 billion.
MISO said the $13.1-billion, 444-project portfolio still is driven mainly by growing load. In spring, the RTO pinned the collection at 434 projects and $11 billion. (See Load Growth Drives Early MTEP 25 to $11B.) MTEP 25 is considered preliminary until late fall; MISO revealed the latest MTEP 25 tallies at a June 10 System Planning Committee meeting of the MISO Board of Directors.
This year’s MTEP is loaded with a record-high 37 expedited project requests valued at $4.36 billion.
Executive Director of Transmission Planning Laura Rauch said six of MTEP 25’s top 10 most expensive projects originated from expedited project requests. MISO’s top 10 projects account for 43% of MTEP 25 spending.
The grid operator said 76% of MTEP 25 projects are due to be in service within three years. MISO said MTEP 25’s project totals contain more than 1,900 miles in transmission lines.
Rauch said the traditional and expedited projects are set to serve about 8.7 GW in new load across the footprint.
During a June 2 East Subregional Planning meeting, MISO’s Scott Goodwin said requests for MISO to expedite MTEP processing of some transmission projects have “exponentially exploded” since 2022, when the RTO fielded only 16.
MISO hopes to pivot to a bimonthly processing approach for the growing number of transmission projects submitted by members for expedited treatment.
Going forward, MISO plans to open an every-other-month acceptance window for expedited project requests. It has said the new cadence should be less cumbersome on staff than MISO’s existing ad-hoc approach.
Currently, MISO evaluates requests as they’re received for transmission projects that cannot wait until end-of-the-year approval through the annual MTEP. MISO originally hoped to roll out a quarterly expedited process but was met with stakeholder resistance. (See MISO Starting from Scratch on New Schedule for Reviewing Expedited Tx Projects.)
MISO plans to study smaller expedited projects in batches while larger, complicated projects will get individual assessments. It said it hoped to debut a 30-day study turnaround for the more straightforward projects.
The grid operator also said it will schedule a single, monthly Technical Study Task Force meeting to discuss expedited projects instead of holding piecemeal, short task force meetings every time a request pops up.
Some stakeholders have asked MISO to consider a load interconnection queue like its generator interconnection queue because of the snowballing expedited requests.
MISO has experienced a runaway volume of expedited requests in recent years as load growth surges. While it used to process an average of six expedited requests annually, since 2021, it has experienced upward of 30 requests. The projects themselves are becoming larger and more complex.
MTEP 25’s expedited investment eclipses MTEP 24’s $896 million worth of expedited requests and MTEP 23’s $684 million.
MISO is set to hold a round of subregional planning meetings to review a more finalized MTEP 25 in September. MTEP 25 goes before the MISO Board of Directors for approval in early December.
