Generation unavailability during extreme cold weather was identified as a high reliability risk in MRO’s 2023 Regional Risk Assessment (RRA).
One of the inputs to the RRA is NERC’s State of Reliability Report (SOR), which identifies system performance trends and emerging risks, reports on the health of the interconnected system, and measures the success of mitigation activities deployed. The 2022 SOR assessed extreme weather challenges in 2021, most notably, the February 2021 extreme cold weather event that resulted in the largest manual load shed event in U.S. history.
Both the RRA and the SOR stress that extreme winter weather continues to pose challenges to generation resource availability by limiting energy supply while demand is increasing. Over the past few years, the number of winter weather events and their subsequent impact on bulk power system reliability have prompted additional efforts from the ERO Enterprise (collectively NERC and the six Regional Entities, of which MRO is one) to mitigate risk associated with extreme winter weather.
On May 15, 2023, NERC issued a Level 3 Essential Actions alert to Industry: Cold Weather Preparations for Extreme Weather Events III. The purpose of the alert is to increase readiness and enhance plans for (and progress toward), mitigating risk for the upcoming winter season and beyond.
NERC distributed the alert to Reliability Coordinators (RCs), Balancing Authorities (BAs), Transmission Operators (TOPs), and Generator Owners (GOs).
The alert presents eight essential actions targeted to different registered functions for BAs, GAs and TOPs based on risk, as well as reporting instructions applicable to each function.
The eight essential actions are:
- Each GO should calculate the Extreme Cold Weather Temperature (ECWT) for each plant location prior to the next winter season.
- Each GO should identify, in the cold weather preparedness plan, the Generator Cold Weather Critical Components and freeze protection measures implemented on those components prior to the next winter season.
- Each GO should identify which units are capable of operating at the ECWT as currently built, and which units require additional freeze protection measures to operate at that temperature.
- Each GO should identify which units experienced a Generator Cold Weather Reliability Event in the 2022–2023 winter season.
- Each TOP should update their operating plan(s) prior to the next winter season, to include provisions to minimize the overlap of circuits that are designated for manual load shed and circuits that are utilized for under frequency load shed (UFLS) or under voltage load shed (UVLS).
- Each BA should update their operating plan(s) prior to the 2023–2024 winter season, to include provisions for TOPs to implement operator controlled manual load shed; and manage generating resources in its BA Area.
- Each GO should provide its RC, BA, and TOP the ECWT for its location prior to the next winter season and whether Generator Cold Weather Critical Component freeze protection measures will not be implemented on components prior to the next winter season.
- Each GO should share their responses with their respective BAs and TOPs to allow for updates to any operating plans before the next winter seasons.
This is the first Level 3 Alert issued by NERC and a webinar was held on May 5, 2023, to discuss the essential actions from the alert and provide an opportunity for industry questions. The recorded webinar can be found here: Streaming Webinar, Webinar Presentation
Notable dates for those subject to the alert:
- Initial distribution of the Level 3 Alert was May 15, 2023
- Acknowledgement is required by Midnight Eastern time on May 22, 2023
- Reporting is required by Midnight Eastern time on October 6, 2023
- This will include responses to alert questions, any supporting documentation along with approval of the responses from appropriate registered entity personnel.
Additional information can be found at:
- Project 2021-07 Extreme Cold Weather Grid Operations, Preparedness, and Coordination
- Petition Of The North American Electric Reliability Corporation For Approval Of Proposed Reliability Standards EOP-011-3 And EOP-012-1 And Request For Expedited Action
- Order Approving Extreme Cold Weather Reliability Standards
Questions from MRO registered entities on the alert should be directed to [email protected].
– Max Desruisseaux, MRO Senior Power Systems Engineer