(Recasts with Thursday's milestone)
July 19 (Reuters) - Homes and businesses in Texas used record amounts of power on Thursday afternoon, breaking the previous record set Wednesday, and are expected to use even more in coming days as consumers crank up air conditioners to escape a brutal heat wave, according to the operator of much of the state's power grid.
The Electric Reliability Council of Texas (ERCOT) said demand reached a system-wide peak of 73,259 megawatts (MW) between 4 and 5 p.m, topping the prior record high of 72,192 MW on Wednesday. One megawatt can power about 1,000 U.S. homes.
To keep air conditioners running, Texas utilities are buying electricity from all sources, keeping power prices near seven-year highs hit earlier in the week.
"We are headed into even more extreme temperatures than we've seen in the past few days. Everyone in the ERCOT market ... is doing what they can to keep the power on for consumers," ERCOT spokeswoman Theresa Gage said in an email.
High temperatures in Houston were expected to reach 98-101 degrees Fahrenheit (37-39 Celsius) every day from July 16-23, according to AccuWeather.
The normal high in Houston, the fourth-largest U.S. city, at this time of year is 94-95 degrees F.
ERCOT had forecast usage would set an all-time high of 73,656 MW on Thursday, followed by 74,698 MW on Friday, 72,681 MW on Saturday, 72,337 MW on Sunday and 76,204 MW on Monday before easing to 73,282 MW on Tuesday and 71,926 MW on July 25.
Power prices at the ERCOT North hub EL-PK-ERTN-SNL slipped to $300 per megawatt hour on Wednesday from $351 on Tuesday, which was the highest since August 2011. That compares with an average of $39.44 so far this year and $26.67 for all of 2017.
Despite the retirement of three big coal plants in early 2018, ERCOT has said it expects to have sufficient operational tools to manage tight reserves and maintain system reliability this summer.
Those tools include using a previously mothballed power plant, imports from other regions, consumer conservation and demand response efforts, which compensate consumers for cutting electric usage.
ERCOT manages the grid for 24 million Texas customers, representing about 90 percent of the state's electric load.
Reporting by Scott DiSavino and Harshith Aranya Editing by Bernadette Baum and Chris Reese