On June 15, 2023, FERC issued two final rules aimed at boosting bulk power system resilience by improving how grid operators assess and plan for extreme weather impacts to the transmission system. One rule directs NERC to develop a reliability standard that requires transmission system planners to account for a range of extreme weather conditions, and the other rule directs each FERC-jurisdictional transmission provider to submit an informational report to the Commission that outlines its policies and processes for conducting extreme weather vulnerability assessments.
Under the existing North American Electric Reliability Corporation (“NERC”) transmission system planning framework, transmission planners and planning coordinators maintain system models that account for existing facilities and load forecasts, but may not necessarily adjust those output and demand forecasts for extreme weather conditions. The first rule, issued in Docket No. RM22-10-000, directs NERC to develop a new or modified reliability standard to require transmission system planning for a range of extreme weather conditions over wide geographical areas. The rule also provides a roadmap for what the new or modified standard should contain. It directs NERC to require planners to (1) develop benchmark models that account for the impact of both extreme heat and extreme cold weather conditions, (2) model how concurrent failures of bulk power system generation and transmission equipment may occur across a range of weather scenarios, and (3) develop corrective action plans where extreme weather is modeled to threaten reliability. “Given the importance of timely addressing the reliability gap,” the Commission explains, NERC must submit a responsive new or modified reliability standard within 18 months of the date of the final rule’s publication in the Federal Register
The second rule, issued in Docket No. RM22-16-000, directs each FERC-jurisdictional transmission provider to submit a one-time, informational report to the Commission that outlines its existing or planned policies and processes for conducting extreme weather vulnerability assessments. FERC explains that each report should include information on how “transmission providers: (1) establish a scope [for vulnerability assessments], (2) develop inputs, (3) identify vulnerabilities and exposure to extreme weather hazards, (4) estimate the costs of impacts in their extreme weather vulnerability assessments; and (5) use the results of those assessments to develop risk mitigation measures.” This rule only solicits information from transmission providers and does not establish new requirements. Each transmission provider must submit its one-time informational report no later than 120 days after the rule’s publication in the Federal Register.