By Amanda Durish Cook
MISO is proposing standalone fixes to its loss-of-load expectation (LOLE) study and capacity accreditation while it still conducts analysis to determine whether it should implement a seasonal capacity construct.
The analysis and proposals are the latest efforts in the RTO’s ongoing resource availability and need (RAN) initiative.
MISO planning adviser Davey Lopez called his presentation at the Resource Adequacy Subcommittee’s meeting Wednesday a “progress report” on the RAN effort, given that MISO suspended presentations on the project in September to allow time for analysis that could drive future draft rules. (See “RAN Respite,” MISO Resource Adequacy Subcomm. Briefs: Sept. 12, 2019.)
Lopez said MISO will finish a detailed analysis on a seasonal construct and have results for stakeholders by January, and that it is still targeting a March filing to change capacity resource accreditation. He said a seasonal construct might provide a more accurate representation of the footprint’s capacity supply.
“We know some resources perform differently throughout the year, and some might not be available all year long,” Lopez said. “We know some resources aren’t participating in our auction because they don’t want to be subject to must-offer all year long.” He said seasonal divisions of capacity supplies could provide the “granularity” that those resources require.
MISO executives this year began publicly questioning the effectiveness of continuing to measure system reliability according to the ability to meet demand during the summer peak hour.
CEO John Bear said the RTO must be mindful of reliability across all hours of the year, with resources being accredited based on availability and market prices incenting availability. He also said an efficient transmission system is needed to accommodate the shifting generation portfolio.
“We’re seeing significant change in our resource portfolio and how it performs. We’re going to need our stakeholders,” Bear said during an Oct. 22 Informational Forum, noting that solutions will become more complex.
MISO’s LOLE modeling assumptions have historically been tailored to covering a summer peak.
“But given that we’ve seen [maximum generation] events in recent history, primarily outside of the summer months … we’re asking ourselves if a summer focus still makes sense,” Lopez said.
Day-ahead offers have decreased since 2014 in relation to generation cleared in the Planning Resource Auction, he said. “Much of our requirement is being made up by emergency-only resources.”
LOLE Modeling and Accreditation Changes
Lopez said a “disconnect” exists between LOLE modeling and resource accreditation. He said MISO needs to better define risks and include seasonal effective outage rates, limitations in load-modifying resource availability and intermittent resource capabilities in its modeling. The LOLE study improvements can be made regardless of whether the RTO moves forward with accreditation changes or a seasonal construct, he said.
MISO could also tie a resource’s accreditation to its day-ahead offers during critical times, possibly using a resource’s day-ahead offers for the bottom 5% tightest margin hours over the last three years to calculate accreditation. The RTO must conduct more analyses to determine the impacts of factoring day-ahead offers into accreditation, Lopez said.
Lopez noted that MISO realizes it could not apply the day-ahead approach to intermittent resources, so it would instead continue to use its effective load carrying capability (ELCC) analysis to determine capacity credits for wind resources. MISO will devise an ELCC for solar generation as penetration increases.
In response to a question from Customized Energy Solutions’ Ted Kuhn, Lopez said using separate ELCC analyses across all resources might be too big a lift for RTO staff, although he would look into the possibility.
At the October RASC meeting, WPPI Energy Assistant Vice President of Planning Todd Komplin questioned what supporting research MISO had performed to verify the need for a seasonal auction or accreditation.
“It seemed that MISO jumped right into a seasonal resource adequacy construct without analysis behind it. We’re not necessarily opposed to a seasonal construct, but the data needs to show a need,” he said. “We haven’t really seen [data], and it’s been quite confusing.”
Komplin argued that more market participants than ever are using MISO’s Maintenance Margin supply look-ahead page and scheduling generation outages more judiciously, minimizing supply shortages.
He also said stakeholders have yet to see a “meaningful” LOLE analysis that reflects loss-of-load risks outside of summer. Customized Energy Solutions’ David Sapper added that MISO hasn’t considered its future resource mix in LOLE studies.
Kuhn also reminded MISO staff that they could consider just adding the now-hot September weather to the RTO’s definition of summer months and forgo capacity seasonality altogether.
MISO has called its short-term RAN fixes a success, reporting that stricter generation outage rules, better LMR availability reporting and annual real power testing for demand response have resulted in 5 to 10 GW of additional availability during times of need.
Dustin Grethen, MISO market design adviser, said this past summer broke a three-year pattern of declining margins and increasing emergency near misses.
“We had our tightest margins day after day after day in the summer of 2016,” Grethen said at the Market Subcommittee meeting in October, adding that 2017 was relatively manageable because of low load, but 2018 was again a study in volatility.
MISO has said its near-term RAN filings were meant to buy time to spell out bigger ideas to rectify supply imbalances brought on by increasing renewable generation.
