MISO said unless stakeholders come up with an alternative it hasn’t explored, it will have to renew its sole system support resource — Manitowoc Public Utilities’ Lakefront 9 coal unit — for another year.

At a Nov. 5 technical study task force meeting, MISO’s Huaitao Zhang said the RTO continues to find steady state thermal violations during the summer months that require mitigation.

He said MISO didn’t land on any transmission reconfiguration options, operating guide substitutions or demand-side solutions that can negate the need for Lakefront 9 staying online to sustain reliability. MISO uses system support resource (SSR) agreements to keep generation operating past planned retirement dates for the sake of system reliability.

Further, Zhang said MISO has ruled out redispatch as a solution because there are limited resources in that area of Wisconsin. Local transmission owner American Transmission Co. (ATC) also discourages manual load shed as a viable mitigation, he said.

If no stakeholders come forward with an alternative that hasn’t occurred to MISO, Zhang said MISO must begin a new SSR term with the municipal utility on Feb. 1. Zhang asked stakeholders to offer their ideas over the next two weeks.

Lakefront 9 has been operating as an SSR since February 2023, after MISO discovered that thermal overloading could occur on several nearby constraints if the plant was permitted to suspend operations as scheduled. Manitowoc Public Utilities originally sought to idle the 63-MW Lakefront 9 until 2026 and to convert it to a renewable fuel source. (See FERC Again Questions MISO Reliability Payments to Wisconsin Coal Plant.)

MISO has said ATC’s planned, 138/69-kV transmission upgrades for the area, which would improve system performance and allow it to lift the SSR agreement, won’t be completed until mid-2028.