North America's electric reliability watchdog said many parts of the U.S. face "elevated risk" of energy emergencies this summer due to a potential combination of extreme heat, droughts, wildfires and tight energy resource capacity.
As a result, the season "is shaping up to be a challenge for electric system operators," the North American Electric Reliability Corp. said in its 2021 summer reliability assessment released May 26.
Weather officials forecast above-normal temperatures across much of North America, while fire agencies project higher-than-normal wildfire risks for the U.S. West Coast, Southwest and parts of Canada. At the same, grid operators are managing a shift away from traditional, fossil fuel-fired generation toward intermittent wind and solar energy, NERC's report noted.
"We really don't know when and how well solar and wind and other weather-dependent resources might perform when the system needs them," John Moura, NERC's director of reliability assessment and technical committees, said during a webinar to discuss the new assessment.
With those factors in mind, NERC identified four areas at heightened risk of energy shortfalls and other disruptions. Resource and energy adequacy across most of the Western Electricity Coordinating Council is a "significant concern," NERC found. The report said capacity and demand projections for the region mirror summer 2020, when a wide-area heat event forced managed load loss in some areas.
California, which is part of WECC, has added flexible resources, but "peak demand projections have also increased in many parts of the West, and overall resource capacity is lower compared to 2020," NERC said. "Increasing demand and lower resource capacity across WECC can mean the availability of surplus capacity for transfer into stressed areas is declining."
The report pointed to probabilistic studies indicating that 10,185 MWh of energy in the California-Mexico assessment area could go unserved this summer. Although the region is expected to add more than 3 GW of resources this summer, most of that will be from solar photovoltaic generation, which drops rapidly in the late afternoon.
The risks could be mitigated by growth in battery storage capacity in California. The state is expected to have 675 MW of new energy storage systems online at the start of summer and add another 825 MW of battery storage during the season, NERC noted. Nevertheless, the report said the California/Mexico portion of WECC was at high risk of energy emergencies in the coming months.
After experiencing massive blackouts this past winter, Texas could also be in for a bumpy summer. On-peak planning reserve margins in the state have grown to 15.3% from 12.9% last summer with the addition of 7,858 MW of wind, solar and battery resources, NERC said. But the summer assessment warned that Texas, which gets a large portion of its electricity from wind facilities, must have enough flexible resources to cover potential periods of low wind output, with the Electric Reliability Council Of Texas Inc. previously encountering energy emergencies during extreme weather.
NERC flagged the Midcontinent ISO and New England as two other regions of concern. Both have sufficient resources for peak demand periods, according to the report. But above-normal demand as outlined in NERC's "90/10" forecast would likely exceed capacity resources in those regions, requiring additional nonfirm power transfers from neighboring areas.
All other parts of the U.S. are at low risk of energy shortfalls in the coming months, NERC said.
"The events of this past year and the outlook for this summer [are] a stark reminder that in our hurry to develop a cleaner resource base, reliability and energy adequacy has to be take into consideration," NERC President and CEO Jim Robb said. "I want to be clear — this is not a call against the transition but rather a plea for attention to the pace of change and the challenges created for system operators."
Recommendations
NERC's summer assessment offered several options for addressing the potential grid challenges.
The organization encouraged load-serving entities and regulators to work with their balancing authorities and reliability coordinators to ensure clear communication during periods of system stress. Balancing authorities and reliability coordinators should also test their alert programs so they are ready to request conservative operations or restrictive maintenance periods and should "maintain the highest vigilance" during peak risk hours and forecast high-temperature periods, the report said.
In addition, NERC suggested that load-serving entities prepare for demand-side conservation measures and review nonfirm customer inventories and rolling blackout procedures to ensure critical infrastructure loads are not affected.
NERC is doing its own work too. Following the winter weather-driven power outages in Texas this past February, Moura said NERC is drafting cold weather standards for grid operators. Although the standards are mainly focused on winterization, they will "highlight extreme weather as well," which could help grid operators enact an "all-hazards approach" to safeguarding the bulk power sector, including from intense heat.