ERCOT starts weather watch earlier
Grid monitor’s forecast shows power demand could break records during state’s deep freeze
The Electric Reliability Council of Texas on Friday extended its earlier warning to say that freezing temperatures could stress the state’s power supply a day earlier than previously expected as it faces the possibility of record-setting power demand next week.
ERCOT initially issued a weather watch alert to begin Monday. On Friday, it amended that notice to begin Sunday and last through Wednesday.
The statewide grid operator said it still expects grid conditions to be normal and that its weather watch alert calls on Texans to monitor conditions.
“The State of Texas is working tirelessly to keep Texans safe and warm as an extraordinarily cold weather system begins to impact our state,” Gov. Greg Abbott said Friday during a news conference. “Texans are urged to be prepared for a multilong period of extreme cold weather and avoid going outside until this winter storm system has passed.”
As of Friday, ERCOT’S forecast for power supply and demand shows that it expects the supply to be sufficient through the long holiday weekend. Come Tuesday, however, ERCOT predicts demand could shatter its previous winter record and potentially beat the overall record for demand set during the recent summer’s crippling heat. ERCOT manages the flow of power for about 90% of the state. As of Friday afternoon, ERCOT’S projections for Tuesday showed demand surpassing 87,500 megawatts at 8 a.m. ERCOT’S record for power usage was set in August at about 85,500 megawatts .during December 2022’s freeze, Texans set a winter demand record of 74,100 megawatts. Demand generally peaks in the morning as people wake up and turn on lights and appliances.
ERCOT’S January analysis shows that during extreme cold — or temperatures similar to those felt during the December
2022 freeze — the grid has a 20.6% chance of hitting a grid emergency in the early morning when solar power isn’t fully available. The chance for rolling outages during the 8.a.m. hour is nearly 17%.
During the 2022 storm, ERCOT’S demand forecasts missed the mark by about 10,000 megawatts. While the grid operator didn’t need to resort to emergency actions at that time, its predictions of how far Texans’ power demand would soar against the cold were low.
“I’m actually encouraged to see the higher forecast,” grid expert and energy analyst Doug Lewin said.
Lewin said the current forecasts shows ERCOT has likely taken federal regulators’ suggestion “to heart” for how to better model the way that demand can increase during extreme cold, especially from homes that use backup heating systems .those homes, Lewin said, can use three to four times more power to keep their homes warm on a 14-degree day than they would to keep it cool during a 100-degree day .lewin said it’s unlikely that Texans’ power use will surpass summer demand records, but it’s possible if temperatures drop low enough statewide. Lewin said longer term, Texas needs to improve homes’ energy efficiency so they better capture the heat during the winter or the cool air during the summer and put less stress on the grid.
As the coldest days near, ERCOT’S supply and demand models are likely to keep changing.
As of Friday afternoon, ERCOT’S demand forecast showed Tuesday evening with a narrow supply cushion. The lines representing supply and demand get closest when solar power drops off as the sun sets. Lewin said wind forecasts for that period are likely also coming in low, affecting the estimated supply even more.
“Really, it’s those kinds of problems batteries and demand response are good to use to solve,” Lewin said.
CPS Energy, for example, has created a new winter demand-response program that moves large users off the grid at times that supply is tight. It also will lower volunteering residences’ thermostats to lessen their collective power load.cps said in a statement this week that it is actively working to increase the number of large users in its demand-response program “to help maintain grid reliability during winter weather events.”
The state’s growing number of battery sites can also deploy power they’ve stored while supply was plentiful to use during emergencies. Batteries helped prevent rolling outages during a September heat wave. Most battery systems in the state sell their power on the reserve market, which ERCOT uses as a lifeline when supplies are tight.
“We have more batteries now than we did over the summer,” Lewin said. “Hopefully, they will be ready to jump in.”