Much of North America, particularly the eastern two-thirds of the continent, are at elevated risk of having insufficient energy supplies to meet demand in extreme operating conditions this winter, according to the North American Electric Reliability Corp.
According to NERC’s 2023–2024 Winter Reliability Assessment, there should be adequate resources to meet normal winter peak demand in those areas, but any prolonged, wide-area cold snaps “will be challenging due to generator outages and fuel vulnerability, extreme levels of electricity demand, difficulties in accurate forecasting and the risk of firm electricity transfer curtailments.”
“Extreme cold weather events can cause electricity demand to deviate significantly from historical forecasts. Electricity demand in winter” is closely tied to outside temperatures, said Mark Olson, NERC’s manager of Reliability Assessments. “As electric heat pumps and heating systems become more prevalent, their combined effect on system demand is even more pronounced. The growth of intermittent resources, like solar generation, on the distribution system significantly increases load forecasting complexity and uncertainty. Once again, we strongly recommend that operators take the necessary steps to prepare for winter.”
In terms of regions that could potentially have insufficient electricity supplies during peak winter conditions, NERC noted that prolonged, wide-area cold snaps could threaten the reliability of the bulk power system and the availability of fuel supplies for natural-gas-fired generation.
In recent winter reliability events, over 20 percent of generating capacity has been forced off-line when freezing temperatures extend over parts of North America that are not typically exposed to such conditions, the NERC report noted. And NERC, said, “when electricity supplies become constrained, system operators can face a simultaneous sharp increase in demand as electric heating systems consume more power in cold temperatures.”
In particular, the NERC report noted that a wide swath of the Southeast, including the PJM, SERC-East, and SERC-Central regions, could experience energy emergencies as a result of sharp increases in generator forced outages and electricity demand. Forecasted peak demand in the region “has risen while resources have changed little in these areas since Winter Storm Elliot caused energy emergencies across the area in 2022,“ NERC said.
The Electric Reliability Council of Texas region is facing a greater risk of reserve shortages than last winter, NERC said, primarily because of robust load growth that is not being met by corresponding growth in dispatchable resources. However, NERC said, “ERCOT is taking steps to procure additional capacity ahead of winter that can reduce the likelihood of energy emergencies.”
The report also noted that the Midcontinent Independent System Operator’s southern region could experience high generator outages from inadequate weatherization or insufficient natural gas fuel supplies.
NERC also noted reserve margins have fallen by eight percentage points from the previous winter due to increased peak demand projections in the Midwest Reliability Organization SaskPower region in Canada where high numbers of forced generator outages or wind turbine cold temperature cutouts could lead to operating reserves shortfalls.
Highlighting the risks posed by cold weather induced natural gas supplies, NERC noted that “recent extreme cold weather events have shown that energy delivery disruptions can have devasting consequences for electric and natural gas consumers in impacted areas.” That is particularly true in the Northeast Power Coordinating Council-New England region where “potential constraints on the fuel delivery systems and the limited inventory of liquid fuels may exacerbate the risks for fuel-based generator outages and output reductions that result in energy emergencies during extreme weather.”
NERC also noted, however, that ISO New England introduced its Inventoried Energy Program this year as an interim measure to address energy security concerns. The program provides compensation for generators that maintain inventoried energy for their assets during extreme cold periods.
Among other risks, the NERC report noted that winter load forecasting is growing in complexity as electrification of the heating sector is increasing temperature-sensitive load components while increasing levels of variable-output solar photovoltaic resources add to the load forecast uncertainty.
NERC also said curtailment of electricity transfers to areas in need during periods of high regional demand is a growing reliability concern.
While curtailments can alleviate an issue in one part of the system, they can contribute to supply shortages or affect local transmission system operations in another area. The NERC report identified several areas at risk from import curtailments, including MRO-SaskPower, NPCC-Maritimes, NPCC-New England, SERC-Central, and SERC-East.
To reduce the risks of energy shortfalls, NERC recommends the following:
- Reliability coordinators, balancing authorities and transmission operators in the elevated risk areas should review seasonal operating plans and the protocols for communicating and resolving potential supply shortfalls in anticipation of potentially high generator outages and extreme demand levels.
- Transmission operators, balancing authorities and generation owners should implement the essential actions identified in the NERC Level 3 alert, Cold Weather Preparations for Extreme Weather Events–III, and should take recommended weatherization steps prior to winter.
- Balancing authorities should be cognizant of the potential for short-term load forecasts to underestimate load in extreme cold weather events and be prepared to take early action to implement protocols and procedures for managing potential reserve deficiencies.
- Reliability coordinators and balancing authorities should implement generator fuel surveys to monitor the adequacy of fuel supplies.
- State and provincial regulators can assist grid owners and operators in advance of and during extreme cold weather by supporting requested environmental and transportation waivers, as well as public appeals for electricity and natural gas conservation
