Powering Strong Communities

Federal Energy Regulators Finalize Rules to Bolster Reliability Against Extreme Weather Threats

The Federal Energy Regulatory Commission on June 15 finalized two rules intended to help improve reliability of the bulk power system against threats of extreme weather.

One rule directs the North American Electric Reliability Corporation to develop a new or modified reliability standard to require transmission system planning for extreme heat and cold weather conditions over wide geographical areas, including studying the impact of concurrent failures of bulk power system generation and transmission equipment and implementing corrective actions as needed.

In a presentation at FERC’s open meeting, Commission staff noted that NERC must develop a new reliability standard or modifications to the current transmission planning Reliability Standard, TPL-001-5.1, no later than 18 months from the date of publication of the final rule in the Federal Register.

Specifically, the final rule directs NERC to develop a new or modified reliability standard that addresses three major concerns. 

First, the draft final rule requires the proposed standard to define benchmark events based on prior extreme heat and cold weather events and/or future meteorological projections. 

Second, the proposed standard must require planning entities to develop planning cases for extreme heat and cold weather events using steady state and transient stability analyses that cover a range of extreme weather scenarios, including the expected resource mix’s availability during extreme weather conditions and the wide-area impacts of extreme weather. 

Third, to the extent these planning studies discover specified instances when performance requirements during extreme heat and cold weather events are not met, the proposed standard must require planners to develop corrective action plans to allow the performance requirements to be met.

The second rule directs transmission providers to submit one-time reports describing their policies and processes for conducting extreme weather vulnerability assessments and identifying mitigation strategies (Docket Nos. RM22-16, AD21-13).

FERC staff noted that an extreme weather vulnerability assessment -- as defined in the final rule -- is any analysis that identifies where and under what conditions jurisdictional transmission assets and operations are at risk from the impacts of extreme weather events, how those risks will manifest themselves, and what the consequences will be for system operations. 

The final rule directs FERC-jurisdictional transmission providers to file one-time informational reports describing how they conduct extreme weather vulnerability assessments, if at all. 

Specifically, transmission providers will need to report how they:  1) establish a scope; 2) develop inputs; 3) identify vulnerabilities and exposure to extreme weather hazards; 4) estimate the costs of impacts; and 5) use the results of vulnerability assessments to develop risk mitigation measures. 

FERC staff said the reports would provide the Commission with a fuller record as to whether and how transmission providers assess and mitigate vulnerabilities to extreme weather and will enable coordination among transmission providers as well as information sharing on best practices.

The final rule reflects certain changes from a related Notice of Proposed Rulemaking, FERC staff said.  The changes include requiring reporting on how transmission providers define extreme weather and requiring reporting on how Regional Transmission Organizations and Independent System Operators account for differences between transmission owner members’ assumptions and results. 

The new rules stem from the Commission’s June 2021 technical conference on Climate Change, Extreme Weather and Electric System Reliability.

Both rules take effect 90 days after publication in the Federal Register.