Officials with Texas' power grid operator pleaded with residents Monday to limit their electrical usage amid soaring temperatures and a series of mechanical problems at power plants.
The appeal, from the Electric Reliability Council of Texas, or ERCOT, comes four months after deadly blackouts during a winter storm left millions of people without power — and weeks after state legislators passed a package of measures aimed at fixing some of the problems exposed by the storm.
Officials with the nonprofit group, which oversees 90 percent of Texas' energy production, asked residents to set their thermostats higher, turn off lights and avoid using larger appliances until Friday.
A spokeswoman for the group told reporters that the outages accounted for more than 12,000 megawatts, enough to power 2.4 million homes. Some areas of the state, including Dallas and Tarrant counties, were warned about poor air quality and potentially dangerous heat, with the heat index approaching 110 degrees.
The index in Houston also topped 100 degrees.
A senior official with ERCOT, Warren Lasher, said it wasn't clear why there were so many unplanned outages. But he said that the group is "deeply concerned" about the plants that are offline and that a thorough investigation is being conducted to better understand the problems.
Officials "need to know why across the fleet are we seeing unplanned, unscheduled mechanical issues," Lasher said.
It was unlikely that controlled blackouts would be instituted Monday, he said.
More than 40 people died during the February storm, many of them from exposure to cold or carbon monoxide poisoning while they were trying to keep warm. Six ERCOT board members resigned in the days that followed. The CEO was fired in March.
Legislators sought this month to strengthen the state's power grid — which isn't subject to federal oversight — through measures that will force companies to winterize parts of the grid deemed critical.
But experts told National Public Radio that the measures aren't enough. One critic told the network that it was an "overstatement" to call new $5,000-per-day penalties for noncompliant companies "a rounding error."