FERC approved new rules Friday likely to reduce load-modifying resources’ (LMRs) capacity accreditation in MISO, despite several protests from RTO members.

The commission said accrediting LMRs based on their notification times and the number of calls they respond to is an appropriate means for managing MISO’s increase in maximum generation emergencies (ER20-1846).

MISO will be able to set an LMR’s capacity accreditation at either an average of its actual availability over a three-year period or its tested availability, whichever is less. LMRs that can respond more often and with shorter lead times will receive a larger capacity credit:

• Those that can respond in six hours or less to 10 or more calls per year will receive full capacity credit.
• LMRs ready in six hours or less that can only respond to five to nine calls in a planning year will receive an 80% accreditation.
• LMRs with lead times greater than six hours will be offered a 50% capacity credit for two years if they can respond to at least 10 calls in a year.

The percentage-based accreditation will take effect in the 2022-2023 planning year. Beginning with the 2023-2024 planning year, MISO will stop offering capacity credits for LMRs with six hours or greater lead times or that cannot respond to at least five calls in a planning year. The RTO maintains that LMRs needing more than six hours’ notice don’t help mitigate emergency conditions.

MISO’s proposal is more lenient than an earlier version that would have eliminated slow-response LMRs two years earlier. (See MISO Delays New LMR Accreditation Launch.)

FERC said the arrangement was reasonable considering MISO’s increased reliance on LMRs to meet its planning reserve margin requirement and the short notice it usually has before entering emergency procedures.

LMRs currently make up nearly 9% of MISO’s planning reserve margin requirement. The grid operator refers to the resources as the last line of defense before having to shed load.

The commission also said MISO’s two-year notice before disqualifying slow-response LMRs gives those resources enough time to adjust their response capabilities and better assist in emergencies.

“We find that MISO’s proposal to reduce the maximum notification time requirement from 12 to six hours reasonably reflects MISO’s ability to predict [maximum generation events] and the ability of LMRs to respond in a timely manner,” FERC said.

The commission said the new rules do not unfairly single out LMRs over other capacity resources, as some LMR-owning members argued. On the contrary, FERC said, MISO’s plan recognizes LMRs’ unique traits.

“We find that MISO’s proposal is not unduly discriminatory against LMRs as compared to other capacity resources because MISO’s proposal addresses the unique operating and reliability characteristics of LMRs, such as advanced notice requirements and that LMR deployments are limited to [maximum generation events] to prevent firm load shedding,” FERC wrote.

MISO isn’t done proposing new solutions to encourage LMR availability. Earlier this month, MISO staff said they must correct significant gaps between the LMR capability that clears capacity auctions and what actually responds to MISO emergency instructions. The grid operator has said several LMRs are unavailable in MISO’s times of need. (See MISO Investigating LMR Availability Problem.)