Much of the U.S. this winter is at an “elevated risk” of having insufficient energy supply to meet electricity demand during extreme cold weather events, a November report from the North American Electric Reliability Corporation finds.

In the eastern two-thirds of North America at elevated risk, there are enough resources for normal winter peak demand. But any long-lasting, widespread 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, according to the NERC report.

In Texas, the risk of reserve shortage is greater than last winter mostly because of the robust load growth that is not being met by corresponding growth in dispatchable resources, the report says. Electricity demand in the state rises sharply as extreme cold weather adds to winter operating challenges and energy shortfall risks.

“Like other assessment areas in the Southern United States, the risk of a significant number of generator forced outages in extreme and prolonged cold temperatures continues to threaten reliability where generators and fuel supply infrastructure are not designed or retrofitted for such conditions,” the winter reliability assessment says about Texas.

Expected resources this winter in Texas will meet operating reserve requirements under normal peak-demand scenarios, the assessment says. Above-normal winter peak load and outage conditions could result in the need to employ operating mitigations (demand response and transfers) and energy emergency alerts. Load shedding is unlikely but may be necessary given widespread cold weather events.

With the El Nino weather pattern expected to firm up this month, Texas can expect more snow and colder temperatures which will surely push electricity use to peak levels.

Is ERCOT up to the task?

“ERCOT expects to have sufficient generation to meet demand this winter,” a spokesperson with The Electric Reliability Council of Texas told the Star-Telegram.

The risk of reserve shortages leading to energy emergency alerts has increased from “low” to “elevated” for the peak load hour. Electricity demand is expected to be 6% higher this year compared to last year in Texas, at 70,451 megawatts for the winter.

The Electric Reliability Council of Texas is taking steps to acquire additional capacity ahead of winter that can reduce the possibility of energy emergencies, the NERC report says. ERCOT also implemented a new firm fuel supply service that’s expected to partially offset the lost generation capacity that can happen when natural gas supplies are limited.

For the cold season, ERCOT will face reserve shortage risks during high net load hours. There is an 11.6% probability this winter that ERCOT will declare a level one energy emergency alert during the highest-risk hour ending at 8 a.m., the NERC assessment says. In the winter, because solar generation is not available to serve peak demand, the system is made dependent on wind generation and dispatchable resource availability to meet the load.

Scarcity risks are higher than last winter mainly due to robust load growth along with insufficient new dispatchable resources to serve the higher net peak loads, NERC says. There’s also been a large increase in thermal units operating under a summer-only schedule, causing an expected loss of 1,283 megawatts of winter capacity.

“ERCOT continues a reliability-first approach to grid operations and will continue to operate the grid conservatively, bringing generating resources online early to mitigate sudden changes in generation or demand,” the spokesperson said.

While ERCOT does not expect any significant fuel supply issues for the winter, fuel-related outages during Winter Storm Elliott last year indicate that natural gas-fired generators experience fuel restrictions during cold weather. ERCOT’s new “Firm Fuel Supply Service,” which was deployed during the storm, is expected to partially offset the lost generation capacity from natural gas restrictions. ERCOT has increasing transmission congestion from South Texas to South-Central Texas that will limit transfers during the winter, the NERC assessment reports.

What will resources look like the coming months?

In December, the expected peak load is 66,200 megawatts, with the total available resources being 81,500 megawatts and 5,100 in total emergency resources. As for January, the expected peak load is 71,700 MW, with the total available resources at 87,200 and the total emergency resources at 5,200.

ERCOT’s monthly outlook for resource adequacy for December and January finds that reserve shortage risks are the highest during the morning hours when daily loads are typically at their highest (8 a.m.), just before and during solar production ramp-up. There is also some elevated risk in the evening due to increasing loads with a secondary peak occurring around 9 p.m.

In December, there’s a low risk of ERCOT having to declare an energy emergency alert during the 8 a.m. peak load hour (5%), but the risk increases to 18% if similar weather conditions to Winter Storm Elliott in December 2022 occur.

In January, on the other hand, there’s an elevated risk of an energy emergency (8%), and the risk increases to 21% if similar weather conditions to Winter Storm Elliott occur.

Under typical grid conditions, there should be sufficient generating capacity available to serve the expected peak load during both December and January, ERCOT says. The capacity reserve margin is higher in December, at 51% for the peak load hour, compared to 44% in January.

The ratio of available dispatchable to available total capacity for the peak load hour at 8 a.m. is about 80% for both months. This helps indicate the extent that the grid relies on dispatchable resources to meet the peak load.

What does NERC recommend?

The increasing prevalence of electric heat pumps and heating systems has had a pronounced effect on system demand in the country. The growth of intermittent resources like solar generation on the distribution system significantly increases load forecasting complexity and uncertainty, NERC says.

NERC strongly recommends that operators take the necessary steps to prepare for winter. NERC also highlights the importance of taking action on the interdependence between bulk power and natural gas systems, including the need for sufficient and reliable gas and electric infrastructure to sustain energy reliability. Along with industry stakeholders, NERC has worked on new cold weather standards aiming to ensure power plants are adequately winterized and prepared for extremely cold temperatures.

NERC’s winter assessment makes several recommendations to reduce the risks of energy shortfalls this winter: grid operators, generator owners and generator operators should implement certain cold weather preparations provided by NERC’s level 3 alert, reliability coordinators and balancing authorities should implement fuel surveys, balancing authorities should anticipate potential for underestimating load in extreme cold and state regulators and policymakers should support reduced electricity and natural gas use.

This story was originally published November 30, 2023, 3:48 PM.