On March 29, 2019, FERC issued an order accepting revisions to the Midcontinent Independent System Operator Inc.’s (“MISO”) Open Access Transmission, Energy, and Operating Reserve Markets Tariff (“Tariff”) to enhance the scheduling of Generator Planned Outages—i.e., the scheduled removal of a generator from service for inspection, maintenance, or repair. While MISO previously managed planned outages through voluntary rescheduling, the Tariff revisions at issue: 1) impose penalties for outages scheduled during low capacity margin, high risk periods, and 2) assist generators in scheduling outages by improving the transparency and quality of generator outage information through MISO’s maintenance margin tool. In accepting MISO’s proposal, FERC concluded that these measures would address recent increases in emergency events by incenting generators to schedule planned outages in advance, and by improving MISO’s ability to coordinate these outages to avoid emergency events.
MISO explains that, as it transitions from a generation portfolio dominated by coal and nuclear generation to a portfolio that relies on an increasing quantity of intermittent and emergency-only resources, its capacity margins have decreased, making it more vulnerable to risks like extreme weather events and natural gas availability. MISO states that these risks are exacerbated in part by similarly-timed Generator Planned Outages, and that such outages have helped to drive a substantial increase in Maximum Generation Emergencies (emergency situations where MISO requires one or more generators to operate at maximum electrical output in order to manage or alleviate the emergency).
MISO’s tariff revisions seek to address this issue by incenting generators to schedule planned outages further in advance. Specifically, MISO will impose an “accreditation penalty” for Generator Planned Outages and derates scheduled less than 14 days in advance and that occur during a Maximum Generation Emergency impacting the MISO sub-region where the generator is located. The penalty will affect the Generator’s capacity accreditation by considering the Generator Planned Outage as a Forced Outage (removal from service due to an emergency, unanticipated failure, inability to return from a planned outage, or other cause beyond the generator’s control) for the purpose of calculating that generator’s forced outage rate for the next applicable planning year. Planned outages and derates submitted between 14 and 119 days in advance may receive an exemption from the penalty if the outage is scheduled entirely within a projected period of low risk with a sufficient resource margin. Planned outages and derates scheduled at least 120 days in advance will generally not be subject to penalty. FERC’s March 29 Order found that this tiered approach will reduce the risks associated with correlated Generator Planned Outages, while maintaining sufficient flexibility for generators to schedule outages without risk of penalty.
MISO also proposed to improve its maintenance margin tool—which provides planned outage and available margin information to generators—by increasing the frequency of posting to twice per week and by providing outage and margin information on both a regional and sub-regional basis. MISO expects that improved forecasts of near- and mid-term generation margins will allow generators to more accurately identify and avoid high risk periods when scheduling planned outages, and will ensure resource availability during times of need. FERC agreed that MISO’s proposal would increase transparency for generators, but required MISO to include the definition of maintenance margin in its Tariff in a subsequent compliance filing.
FERC’s order is available here.