Sign up for The Brief, our daily newsletter that keeps readers up to speed on the most essential Texas news.

Texas’ main power grid struggled to keep up with the demand for electricity Monday, prompting the operator to ask Texans to conserve power until Friday.

The Electric Reliability Council of Texas said in a statement Monday that a significant number of unexpected power plant outages combined with expected record use of electricity due to hot weather has resulted in tight grid conditions. Approximately 12,000 megawatts of generation were offline Monday, or enough to power 2.4 million homes on a hot summer day.

ERCOT officials said the power plant outages were unexpected — and could not provide details as to what could be causing them.

“I don’t have any potential reasons [for the plant outages] that I can share at this time,” said Warren Lasher, ERCOT senior director of systems planning, during a Monday call with media. “It is not consistent with fleet performance that we have seen over the last few summers.”

The number of plants that were forced offline today is “very concerning” Lasher said.

“We operate the grid with the resources that we have available,” he said. “It’s the responsibility of the generators to make sure their plants are available when demand is high.”

The conservation request comes at a time of heightened anxiety around electricity following the state’s catastrophic February power outages that left millions without power for days. Those outages that were prompted by a severe winter storm may have killed as many as 700 people, according to an analysis of mortality data by Buzzfeed news.

Of the plants offline, about 9,600 megawatts of power, or nearly 80% of the outages, are from thermal power sources, which in Texas are largely natural gas-fired power plants. That's several times what ERCOT usually sees offline for thermal generation maintenance during a summer day. Typically, only about 3,600 megawatts of thermal generation is offline this time of year.

“This is unusual for this early in the summer season,” said Woody Rickerson, ERCOT vice president of grid planning and operations, in a statement. He said the grid operator would conduct an analysis to determine why so many units are offline.

At this time, it “appears unlikely” that the ERCOT grid would need to implement outages, like it did in February, to reduce strain on the grid, said Warren Lasher, ERCOT senior director of systems planning, during a Monday call with media.

In April, ERCOT asked residents to cut back power use due to a high number of plants offline for maintenance, some due to repairs necessary from damage during the February winter storm.

Lasher said that ERCOT has completed 20 plant visits ahead of the summer peak season, and 11 more are scheduled for the next 2 weeks. Four of the plants that were inspected are currently on outage, Lasher said.

The high number of outages this week combined with expected record demand: The grid operator estimates demand for electricity could exceed 73,000 megawatts on Monday. The previous record for June was 69,100 megawatts in 2018.

"[Electricity demand] is really driven by temperatures, and right now it is 99 degrees in Dallas, 97 degrees in Austin, and 97 degrees in Houston," said Joshua Rhodes, research associate at the Webber Energy Group at the University of Texas at Austin. He said at those high temperatures, people tend to crank up their air conditioning, which strains the grid. At the same time, he said, power plants have already had a rough year given the February outages that caused damage, which may be causing new complications.

Texans can reduce electricity use by setting the thermostat to 78 degrees or higher; turning off lights and pool pumps; avoiding use of large appliances such as ovens, washing machines and dryers; and turning off or unplugging unused electric appliances.

Power grids must keep supply and demand in balance at all times. When Texas’ grid falls below its safety margin of excess supply, the grid operator starts taking additional precautions to avoid blackouts. The first precaution is to ask the public to cut back electricity usage.

Following criticism that the grid operator did not consider severe enough scenarios in its planning, ERCOT outlined the most extreme calculations for this summer that it has ever considered. ERCOT warned in its summer assessment of power resources that a severe heat wave or drought combined with high demand for power could put the grid in jeopardy. (Texas is expected to have a hotter and drier summer than normal this year, according to an April climate outlook from the National Oceanic and Atmospheric Administration).

During the recent Legislative session, Texas lawmakers passed a suite of energy grid legislation that aimed to prevent electricity blackouts in response to the February crisis. Senate Bills 2 and 3 included a few key changes to the state’s power grid that experts said will begin to address some issues, such as requiring power companies to upgrade plants to withstand more extreme weather and creating a statewide emergency alert system. However, it will likely take years before those changes are fully implemented.

The legislation also changes ERCOT's governing board to replace what lawmakers called "industry insiders" with appointees selected by a committee comprised of selections by Gov. Greg Abbott, Lt. Gov. Dan Patrick and House Speaker Dade Phelan.

The state likely won’t require companies to make weatherization upgrades until 2022 at the earliest.

This article originally appeared in The Texas Tribune at https://www.texastribune.org/2021/06/14/texas-power-grid-conserve-ercot/.

The Texas Tribune is a member-supported, nonpartisan newsroom informing and engaging Texans on state politics and policy. Learn more at texastribune.org.

The Texas Tribune is a nonpartisan, nonprofit media organization that informs Texans — and engages with them – about public policy, politics, government and statewide issues.