An unplanned nuclear outage during a heat wave on Friday has triggered Texas’s new electrical emergency response plan, Dallas TV station WFAA reported. Vistra Corp.’s Comanche Peak 1,200-MW unit 1 scrammed after a problem with a feedwater pump, shutting down enough power to provide some 250,000 customers. The ABC affiliate reported, “Texans will likely set electricity demand records twice this week, when temperatures soar to triple digits.”
The event caused the Electric Reliability Council of Texas (ERCOT) to activate its new Contingency Reserve Service, launched June 10. Under the new plan, ERCOT buys day-ahead ancillary services, the state transmission system operator says, “to balance the next day’s supply and demand of electricity on the grid and mitigate real-time operational issues. Ancillary services can be provided by generators or consumers to increase or decrease the supply of electricity in a matter of minutes or even seconds.”
Chief among the services ERCOT is buying is backup battery storage.
According to WFAA, the new plan also launched briefly on June 14. No details of how much battery storage was used during either use of the new contingency service. In both cases, traditional generation was quickly restored. “Our teams worked diligently to assess and fix the equipment and were quickly able to get the unit back online,” Vistra’s Meranda Cohn told WFAA.
Texas has four nuclear units, each with about 1,200-MW of nameplate capacity. The two Comanche Peak units are Westinghouse pressurized water reactors that went into service in 1990 and 1993. The South Texas Project also has two 1,200-MW Westinghouse PWRs, which went into service in 1988 and 1989.
Ironically, the Texas electric weather emergency took place shortly as the Federal Energy Regulatory Commission in Washington June 15 approved two rules designed to improve the storm and severe weather response of the nation’s electrical system. FERC’s action was a response to a crippling winter storm covering most of the continental U.S. and parts of Canada over the Christmas holiday season last year – which The Weather Channel unofficially dubbed “Winter Storm Elliott”.
The National Oceanic and Atmospheric Administration described the event that triggered FERC’s actions: “On December 21-25, a powerful arctic front wreaked havoc across much of the nation, bringing heavy rains, snow, ice and high winds, and sending temperatures plummeting at record speed. The National Weather Service reported that some 240 million people – more than two-thirds of the U.S. population – were under winter weather warnings and advisories on December 23.”
In its first order (RM22-10) FERC told the North American Electric Reliability Corporation (NERC) to come up with a reliability standard to, in the words of a FERC news release, “to require transmission system planning for extreme heat and cold weather conditions over wide geographical areas, including studying the impact of concurrent failures of bulk power system generation and transmission equipment and implementing corrective actions as needed.”
Second (RM-22-16), FERC ordered transmission providers to produce one-time reports describing their policies and processes for conducting extreme weather vulnerability assessments and identifying mitigation strategies.
FERC chairman Willie Phillips said, “For the first time, reliability standards will require planning for extreme heat and cold weather. NERC will develop the standards, and once we approve them transmission owners and operators will identify the elements of their systems that are vulnerable to extreme heat and cold and develop solutions to address those vulnerabilities.”
The commission adopted the two new rules after a presentation by its staff, which found, “Peak winter electricity demands, coupled with significant unplanned electric generation supply losses exceeding 70,000 MW, occurred during the coldest weather across the Southeastern, Mid-Atlantic, Midwest, and Northeastern U.S..” The main causes of the generating outages, according to the staff, were freezing, mechanical/electrical, and fuel issues.
A major feature of Elliott’s impacts was a massive failure of the natural gas supply and transportation systems. According to the staff report, this failure was also a factor of three of the past five extreme cold weather events that produced major electrical outages since 2011. In four out of the five extreme storms, actual electric demand exceeded utility peak forecasts.
At the commission meeting, Commissioner Allison Clements said, “It shows that reserve margins are an increasingly inadequate tool to predict winter sufficiency,” she said. “Two of the regions that suffered rolling outages during Winter Storm Elliott — TVA and Duke [Energy] — were not even identified in NERC’s 2022-23 winter assessment as anything more than a low risk of load shed.”
FERC’s news release noted, “Since 2011, the country has experienced at least seven major extreme weather events, each of which stressed electric grid operations.” Those include both extreme cold, floods, wildfires, and extreme heat. In a Tweet, Clements said, “The reality is these events will only become more common, and the need for reality-based planning to shore up system resilience more urgent.”
Texas has been particularly plagued with weather-related outages, in part because it is prone to summer and winter extremes, and also because ERCOT has been extremely limited in its ability to interconnect with surrounding grids since its inception, in order to escape federal jurisdiction under the Federal Power Act.
Texas has also been at the forefront of installing renewable solar and wind generating resources, despite the power of the oil and gas industry in the Lone Star State and political posturing by Republican office holders opposing renewables (while benefiting from them). Wind and solar, and now battery storage, have rescued the Texas grid when conventional generating technologies have failed.
–Kennedy Maize