The North American Electric Reliability Corp. (NERC) warned in its 2022-2023 Winter Reliability Assessment that a large portion of the North American bulk power system is at risk of having insufficient energy supplies during severe winter weather. 

Fuel supply issues appear prominently in this year’s assessment, NERC said, adding that reliability coordinators 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. 

NERC said that while the grid has a sufficient supply of capacity resources under normal winter conditions, it is “concerned that some areas are highly vulnerable” to extreme and prolonged cold. As a result, load-shedding may be required to maintain reliability.”

The assessment said that high peak-demand projections, inadequate generator weatherization, fuel supply risks, and limited natural gas infrastructure are contributory factors to reliability risk. 

NERC’s winter reliability risk area summary. Credit: NERC

Regions at particular risk this winter include:

• Texas, SERC-East and southern parts of MISO risk 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.” Peak electricity demand which rises during extreme cold which “compounds the risk.”

• Midcontinent ISO (MISO) has retired more than 4.2 GW of nuclear and coal- fired generation since last winter, with few resources added. Consequently, reserve margins in the region have fallen by more than 5%. 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.

 • 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.

• Alberta and NPCC-Maritimes both project that peak electricity demand will grow in these winter- peaking systems. In the Maritimes, this could strain capacity for normal winter peak conditions. Alberta has sufficient capacity for normal winter peak demand; however, extreme conditions that cause high generator forced outages are likely to cause energy emergencies.

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

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

• Cold weather preparations: Generators should prepare for winter conditions and communicate with grid operators.

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

• State regulators and policymakers: States regulators should preserve critical generation resources at risk of retirement prior to the winter season and support requests for environmental and transportation waivers. In New England, the states should support fuel replenishment efforts.

Read the assessment here.

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