July 20 (Reuters) - Homes and businesses in Texas used record amounts of power for a second straight day on Thursday and are expected to use even more in the 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.
To keep those air conditioners humming, Texas utilities are buying electricity from all sources, which boosted power prices to a near seven-year high earlier in the week.
The Electric Reliability Council of Texas (ERCOT) said demand reached 73,259 megawatts on Thursday, topping the prior all-time high of 72,192 MW on Wednesday. One megawatt can power about 1,000 U.S. homes.
That topped the grid's forecast high of 72,756 MW for this summer.
High temperatures in Houston were expected to reach 99-102 degrees Fahrenheit (37-39 Celsius) every day from July 16-23, according to AccuWeather. The 101-102 degree highs forecast for Friday-Monday would break record highs for those days set in 2000 and 2016.
The normal high in Houston, the fourth-largest U.S. city, at this time of year is 94-95 degrees F.
ERCOT forecast usage would set a new high of 73,273 on Friday before slipping to 72,828 MW on Saturday and 72,487 MW on Sunday, as many businesses close for the weekend.
On Monday, which is expected to be the hottest day of this lingering heat wave, ERCOT projected usage would spike to another new high of 75,597 MW before temperatures and demand ease later in the week.
Power prices at the ERCOT North hub EL-PK-ERTN-SNL fell to a still relatively high $176 per megawatt hour on Thursday from $300 on Wednesday and a near seven-year high of $351 on Tuesday. That compares with an average of $41.33 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.
The biggest power utilities in Texas include units of Sempra Energy, CenterPoint Energy Inc and American Electric Power Co Inc.
Reporting by Scott DiSavino; Editing by Bernadette Baum