NEW ORLEANS — MISO announced March 12 that it will ask FERC for a postponement on rolling out ambient-adjusted line ratings until December 2028.
MISO leadership told the Advisory Committee, meeting as part of MISO Board Week, that RTOs are experiencing delays from vendors supplying the necessary software for the varied line ratings required under FERC Order 881.
Some stakeholders seemed taken aback by the announcement. Clean Grid Alliance’s Beth Soholt said it was disappointing that MISO was not prepared for Order 881 when it previously said adjusted line ratings would not be a particularly heavy lift.
“It’s a consistent theme that systems are not ready to go,” Soholt said of compliance with FERC rulemakings.
Order 881 is set to go into effect for MISO on July 12.
MISO Senior Vice President Todd Hillman said the RTO is not the only grid operator requesting extra time on compliance. He said that although it is unfortunate, it is simply a reality because the country’s RTOs are vying for deliveries from a few specialized vendors to track and implement AARs.
“We’re counting on MISO for the system of the future,” Soholt said, later adding, “excuses, excuses, excuses” in response to Hillman’s explanation. Hillman and Soholt continued in a tense exchange, in which he said he felt the news of the delay was akin to disappointing his mother, to which Soholt responded that she would play the role of dissatisfied parent.
“The vendor stuff is not immaterial. There are a small number of vendors working for all the RTOs,” Hillman said. It’s worth it for MISO and its “RTO brethren” to take the time to get implementation right, he argued.
MISO said over 2022 and 2023 that it had been able to receive and use variable line ratings for about a decade, albeit on a smaller scale. (See MISO, Members Debate Deploying AARs.) At the time, MISO staff said it was up to transmission owners to determine and submit their AARs while the RTO devised an interface to accept and share hourly line ratings.
