According to the 2022-2023 “Winter Reliability Assessment,” published last week by the North American Electric Reliability Corporation (NERC), a large portion of the North American bulk power system is at risk of having insufficient energy supplies available during severe winter weather.

As a result, NERC advises the industry to be ready to implement operating plans to manage potential supply shortfalls, to ensure that fuel supplies are secured, and to make sure that generators and natural gas facilities are weatherized.

Undertaken annually in coordination with the Regional Entities, NERC’s “Winter Reliability Assessment” examines multiple factors that collectively provide deep and unique insights into reliability risk. These factors include resource adequacy that encompass reserve margins and scenarios in order to identify operational risk, fuel assurance, and preparations to mitigate reliability concerns.

“Fuel supply issues appear prominently in this year’s assessment,” said John Moura, NERC’s director of reliability assessment and performance analysis. “Reliability coordinators across North America are closely monitoring the coal and liquid fuel inventories, as well as the potential impacts that transportation disruptions can have on availability and replenishment of all fuels,” In addition, according to Moura, while the grid has a sufficient supply of capacity resources under normal winter conditions, NERC is concerned that some areas will be highly vulnerable to extreme and prolonged cold. “As a result, load-shedding may be required to maintain reliability,” he said.

NERC’s assessment finds that high peak-demand projections, inadequate generator weatherization, fuel supply risks, and limited natural gas infrastructure are contributing factors to the reliability risk. Regions at particular risk this winter include:

• ERCOT (Texas), SERC-East, and southern parts of Midcontinent ISO (MISO) risk having a significant number of generator-forced outages in extreme and prolonged cold temperatures. “Generators and fuel supply infrastructure are not designed for such conditions and remain vulnerable without weatherization upgrades,” said NERC. “Peak electricity demand increases substantially during extreme cold, which compounds the risk.”
• MISO has retired more than 4.2 GW of nuclear and coal-fired generation since last winter, with few resources being added, according to NERC. Consequently, reserve margins in the region have fallen by more than five percent. “An extreme cold-weather event that extends deep into MISO’s area could lead to high generator outages from inadequate weatherization in southern units and unavailability of fuel for natural-gas-fired generators,” said NERC.
• The report added that ISO New England has limited natural gas transportation capacity and relies on liquefied natural gas and oil-fired generators on peak demand days. “Potential constraints on the fuel delivery systems, coupled with 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,” said NERC.

The assessment acknowledges that progress has been made by the industry to improve generator performance since Winter Storm Uri in 2021. “While the risk of energy emergencies in the three areas hardest hit during that event have not been eliminated, enhancements to equipment freeze protection and cold weather preparations for both the gas and electric industries are a positive step,” said Mark Olson, NERC’s manager of reliability assessments.

To reduce the risks of energy shortfalls on the bulk power system this winter, NERC recommends the following actions:

1 – Cold Weather Preparations: Generators should, while considering NERC’s “Cold Weather
Preparations for Extreme Weather Events–II” alert, prepare for winter conditions and communicate with grid operators.

2 – Fuel: Generators should take early action to assure sufficient fuel, and should also communicate plant availability. Reliability coordinators and balancing authorities should monitor fuel supply adequacy, prepare and train for energy emergencies, and test protocols.

3 – State Regulators and Policymakers: State regulators should preserve critical generation
resources that are at risk of retirement prior to the winter season and support requests for environmental and transportation waivers. They should also support electric load and natural gas local distribution company conservation and public appeals during emergencies. In New England, said NERC, the states should support fuel replenishment efforts using all means possible.