Rotating blackouts occur when power companies cut electricity to residential neighborhoods and small businesses, typically for 10 to 45 minutes before being transferred to another location, said ERCOT. Traffic lights and infrastructure can also lose energy during these blackouts.
High temperatures were forecast for Dallas on Monday, while Houston expected high temperatures in the mid-20s.
The city recommended that people save energy by lowering the thermostat to 20 degrees Celsius, turning off non-essential lights and appliances, opening curtains during the day to allow sunlight and closing curtains at night to reduce heat loss.
Houston Police Department chief Art Acevedo said the blackouts caused several police facilities to operate on emergency generators.
“Reduce the load on the power grid, keeping usage to a minimum,” tweeted Acevedo on Monday.
ERCOT ordered continuous interruptions around 1:30 am, local time (2:30 am ET) on Monday. ERCOT set a new peak in winter electricity demand between 6 pm and 7 pm on Sunday, surpassing the old record of January 2018, ERCOT said in a tweet.
Entergy Texas, which supplies power to approximately 461,000 customers in 27 counties in the state, according to its website, said it started outages on Monday.
“We apologize for the inconvenience these disruptions can cause, but we have an unusual situation at the moment, driven by extreme weather conditions. We are working to safely respond and restore power as soon as possible,” said Stuart Barrett, vice president of the client service.
“While our teams were working to prepare for this storm, a generation loss combined with peak load caused a system stress. As a result, we are lacking the power needed to meet the demands of our customers in Southeast Texas.”
CNN meteorologist Tyler Mauldin contributed to this story.