MRO released its 2023 Regional Winter Assessment (2023 RWA) on November 30, which was followed by a webinar on December 12. The assessment provides information and awareness to industry leaders and registered entities, regulatory agencies, and other key stakeholders on the expected health of the bulk power system within MRO’s regional footprint for the upcoming winter season. Complementing NERC’s Winter Reliability Assessment that evaluates resource and transmission system adequacy necessary to meet projected winter peak demands across all North America, MRO’s 2023 RWA takes a more granular look at reliability challenges that present a greater risk within MRO’s regional footprint and includes historical trends.

The 2023 RWA highlights the risk of potential energy shortfalls this winter for Saskatchewan Power Corporation (SPC) during periods of normal weather when combined with planned and/or forced generation outages. Midcontinent Independent System Operator (MISO) and Southwest Power Pool (SPP) also face potential energy shortfalls during extreme winter peak forecast scenarios. SPC is projecting insufficient capacity available to meet forecasted seasonal peak load with typical maintenance and forced outages, which may require implementation of emergency operating procedures like demand response programs and/or short-term power transfers from neighboring utilities to meet operating reserve requirements. SPC’s reserve margins fell this winter by eight percent when compared to last winter due to generation retirements, increased peak demand projections, and planned maintenance outages.

Extreme winter weather may result in insufficient capacity to cover anticipated extreme winter peak demands, placing MISO, SPC and SPP at risk of implementing Energy Emergency Alerts (EEAs). Additionally, potential natural gas supply issues could be a reliability concern for MISO and SPP for the upcoming winter during extreme cold temperatures. Historical trends indicate that conventional generation availability, particularly steam turbine and simple cycle gas plants, is most challenging during winter months and should remain an area of focus. Relay failure/malfunction-related misoperations accounted for nearly a quarter of last winter’s total misoperations. However, misoperations due to human error saw significant improvement over the previous winter season.

The report recommends grid operators maintain situational awareness of fuel risk, unplanned generation and transmission outages during abnormal extreme weather conditions and low wind forecast periods, and employ operating procedures as needed to ensure adequate resource availability.

State and provincial regulators should be prepared to assist grid operators prior to and during the winter season by supporting requested environmental and transportation waivers as well as public appeals for electric load and natural gas conservation.

Topics discussed during the webinar were:

• Resource adequacy analysis and the driving force behind resource shortfalls for winter 2023
• Reliability impacts of historical MRO regional conventional generation forced outage rates
• Performance of BES transmission lines and outages based on circuit miles
• MRO historical operations and misoperations of the protection system and the outage causes during winter months

A recording of the webinar will be available on MRO’s website here.

– Salva Andiappan, MRO Principal Reliability Assessment Engineer