CARMEL, Ind. — MISO said it will finalize an availability-based accreditation for nearly 12 GW of load-modifying resources (LMRs) over the first quarter of 2025 ahead of a filing with FERC.
Some stakeholders remain skeptical of MISO’s plans to rely on past performance levels to accredit LMRs by the 2028/29 planning year.
During a special Dec. 17 Resource Adequacy Subcommittee teleconference, MISO reiterated that it plans to split LMRs into two categories — those that can respond in 30 minutes or less and those that can’t — and accredit them correspondingly.
The RTO said its faster category would have a maximum response time of 30 minutes and presumed availability for all maximum generation emergency step two events.
On the other hand, the class of LMRs with slower response times would carry a maximum response time of six hours and would be readied earlier under tight conditions, when MISO declares a maximum generation warning. The RTO has long said it needs to be able to access LMRs before emergencies materialize.
MISO said the accreditation will extend to demand response resources participating in the capacity auction. Like the slower LMRs, demand response capacity resources would have a six-hour response requirement and must respond to at least one deployment per season if MISO issues instructions, with reduced accreditation for non-response.
Joshua Schabla, a MISO market design economist, said the RTO doesn’t expect to make major changes to the proposal in the coming months.
“The design is in a good spot. That’s not to mean it’s locked in, or we don’t expect a back and forth,” Schabla said. He added that MISO’s existing LMR accreditation is more than 15 years old and doesn’t reflect performance.
MISO has characterized the two classes of LMRs as “rapid” or “flexible.” However, some stakeholders have said it’s unrealistic to expect load reductions in 30 minutes or less, with many LMRs reasonably being able to respond within two hours. (See “New LMR Accreditation Looks Certain,” MISO Demand Response Under Increasing Scrutiny; IMM Warns of More Potential Schemes and MISO Tries to Win over Stakeholders on New LMR Capacity Accreditation.)
MISO said it will use backward-looking meter data from hours when capacity advisory declarations are in place to gauge availability and accredit resources.
The RTO plans to draw on data from a minimum of 65 historical hours per season over the past year, giving equal weighting to performance during low-margin hours and in hours where capacity advisories escalated into maximum generation events, alerts or warnings. That’s a change from fall, when MISO said it would apply a 20% weighting to low-margin hours and an 80% weighting to capacity advisories and above.
“It’s a very broad framework to capture a very broad set of resources,” Schabla said.
Multiple stakeholders said the accreditation plan still seems too complex and destined to produce unintended consequences.
“We’re seeing accreditation not aligned with what these resources are capable of,” Schabla said. “The stack of resources we can rely on is shrinking.”
Schabla said emergency resources can currently clear the capacity auction “without making themselves available.” MISO said real-time availability data indicates anywhere from 6 to 7 GW of capability from an estimated 9.5 GW participation level, which is “far less” than the auction’s cleared quantity of 12 GW of LMRs.
Schabla said the new accreditation will link availability with accreditation and will motivate demand response operators to give MISO accurate availability data.
MISO said it would also halt its practice of accepting LMRs’ self-conducted testing to verify performance.
Schabla said it’s clear that LMRs’ self-testing is not providing a “good indication” of what the resources can do. He said rolling out MISO-initiated testing will keep cheaper resources that cannot perform from crowding out genuine demand response in the capacity auction.
