The Federal Energy Regulatory Commission heard broad support for a proposed rule designed to safeguard the U.S. electric transmission system against extreme weather events, but commenters also offered a range of recommendations on how the proposal could be strengthened.

FERC issued the proposed rule (RM22-10) in June, citing the need for more robust planning measures as severe hot and cold weather events threaten the reliability of the nation's bulk power system.

The North American Electric Reliability Corp., which develops grid reliability standards, warned in its latest summer assessment that a wide-area extreme heat event in the U.S. West could cause emergency power shutoffs in part due to limited transmission transfer capacity.

Grid operators such as the Electric Reliability Council Of Texas Inc. are also still dealing with the fallout from a mid-February 2021 extreme cold weather event that knocked out power for millions of customers across the state.

FERC's proposed rule would require NERC to modify one of its reliability standards to require benchmark planning cases based on previous extreme heat and cold weather events. The proposal would also require corrective action plans that address instances where performance requirements under those conditions are not met.

Comments on the proposed rule were due Aug. 26.

Mixed views on scope of rulemaking

Public interest organizations and clean energy trade groups expressed support for the proposed rule but argued it should be refined in key ways.

A coalition led by the Natural Resources Defense Council's Sustainable FERC Project said the commission should specifically require responsible entities to evaluate a range of potential solutions when crafting their corrective action plans.

Those could include "transmission upgrades, improvements to transmission scheduling practices or seams coordination that increase transfer capacity, grid-enhancing technologies, battery storage and energy efficiency, and demand response," the coalition said.

The coalition also asked FERC to clarify that NERC's revised reliability standard should account for correlated conventional generator outages "of all types." The organizations noted that a joint FERC-NERC investigation into the Texas blackouts found that natural gas-fired generators accounted for 58% of unplanned outages and derates during the winter storm.

The American Clean Power Association and Americans for a Clean Energy Grid also suggested that FERC could use the proceeding to require a minimum level of transfer capacity between balancing areas.

FERC heard support for that idea from state utility commissioners during a recent joint federal-state transmission task force meeting.

"An interregional capacity requirement could be included in the [NERC standard ... and] should be based on the geographic diversity in load, conventional generator outage and renewable output between neighboring regions," Americans for a Clean Energy Grid said.

American Electric Power Service Corp., one of the nation's largest transmission owners, also urged FERC to establish minimum transfer requirements.

"This transfer capability will allow for increased economic transfers during both emergency and non-emergency situations, making lower cost generation available to customers at all times," the company said.

However, ERCOT argued that planners in neighboring areas "cannot be required to adopt a planning solution that would depend on the consent of some other entity."

The Texas grid is almost entirely siloed from the rest of the U.S. transmission system, which allows the state to largely avoid FERC's jurisdiction.

"Planners in neighboring areas may jointly decide to pursue an interregional project based on reliability and/or economic benefits identified in each of their systems; but explicitly or implicitly requiring planners to pursue such projects as part of a corrective action plan under the framework of [the NERC standard] is incompatible with the necessarily limited scope of planning studies conducted under that standard," ERCOT said.

Meanwhile, transmission owners in the U.S. West and Southeast said FERC should ensure that planning cases account for future climate projections.

"Planning cases should be defined based on how the climate, load and generation are changing rather than on conditions that have been seen in the past," Southern California Edison Co. said.

New Orleans-based Entergy Services LLC, whose system was pummeled last year by Hurricane Ida, agreed.

"Use of benchmark events should not result in transmission planning that is tethered to the way a system performs under an event that may have happened years ago," the Entergy Corp. subsidiary said.

Multiple parties also urged FERC to include drought in its list of extreme weather events, noting long-term drought in the U.S. West has caused severe shortfalls in hydroelectric generation.

Regional flexibility

The Edison Electric Institute was joined by the American Public Power Association and National Rural Electric Cooperative Association in calling for a final rule that recognizes variation in regional grid challenges.

"Any new or modified transmission planning performance standard must account for varying challenges and other factors continent-wide, as well as across each utility's service territory; the nature and scope of each utility's system; and the applicable regulatory framework," the trade groups said.

A coalition of transmission owners in the 15-state Midcontinent ISO region also stressed that reliability planning is best done at the regional level.

"Regional entities are better suited to lead on such planning in their roles as planning coordinators," the transmission owners said.

On a related note, the PJM Interconnection LLC — whose footprint covers 13 Mid-Atlantic states — expressed concern that the proposal could hamper its planning efforts by shifting more responsibility to NERC.

The proposed rule may "inadvertently create a singular and somewhat siloed approach that is ... unnecessarily distanced from key PJM stakeholders who are already engaged with PJM in planning for extreme hot and cold weather events in many respects," the regional grid operator said.

For its part, NERC recommended that FERC align the implementation timeline for a final rule with a separate proposal (RM22-16; AD21-13), also issued in June, that would require transmission providers to submit one-time informational reports on how they assess and respond to extreme weather vulnerabilities.

"This information regarding current industry practices and procedures, particularly as they relate to reliability, may prove useful to the NERC standard development process," NERC said.

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