Federal regulators should reject the North American Electric Reliability Corp.’s latest proposed cold weather reliability standards for power plants, according to the PJM Interconnection and other major grid operators.

“Settling for the standard that NERC has filed in this proceeding, with its glaring exceptions and vague requirements, will only result in reliability issues that the Commission will need to address later and at a greater cost to generator owners and the public,” the ISO/RTO Council said in a Friday filing at the Federal Energy Regulatory Commission.

NERC’s mid-February proposal sets a “low winterization bar” and includes “inappropriate exceptions” that will hurt grid reliability, according to the council — which represents the Alberta Electric System Operator; the California Independent System Operator; the Electric Reliability Council of Texas; the Independent Electricity System Operator of Ontario; ISO New England; the Midcontinent Independent System Operator; the New York Independent System Operator; the PJM Interconnection; and the Southwest Power Pool.

NERC’s proposal comes as large numbers of power plants failed to run during winter storms Uri in 2021 and Elliott in 2022, in some cases leading to major power outages. FERC, which must approve NERC standards, directed the grid watchdog organization to bolster its standards in a February 2023 decision.

NERC struggled to gain approval for its proposal during its standards development process.

Among other things, the ISO/RTO Council objects to NERC’s proposal to allow power plant owners to declare a “Generator Cold Weather Constraint” that would excuse them from putting in place freeze protection measures if they cannot be implemented at a “reasonable cost consistent with good business practices, reliability, or safety.”

“Enforcing the standard when this exception is invoked effectively injects NERC and the Regional Entities into the process of judging the reasonableness of costs, cost estimates, and even the particular Generator Owner’s specific financial situation,” the council said.

Cost issues are important, but should be addressed by FERC and state regulators instead of by NERC, according to the council.

“Constraint declarations based on claims of unreasonable costs will prove to be difficult or impossible to audit effectively and consistently,” the ISO/RTO Council said.

FERC should give NERC 120 days to revise its proposal, according to the council.

The New England Power Generators Association doesn’t oppose NERC’s proposal, but warned FERC that ISO-NE’s tariff likely doesn’t allow generators to include the costs of meeting the standards in their energy market bids.

“Generator owners could be left with uncompensated costs for actions they took on a timely basis to comply with the standards,” NEPGA said. “Generator owners should not be left in this legal limbo.”

The trade group urged FERC to clarify how power plant owners can recover their compliance costs in wholesale power markets.