(Adds ERCOT comment, latest demand forecast for Friday)
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 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 air conditioners humming, Texas utilities are buying electricity from all sources, boosting 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 usually power about 1,000 U.S. homes. But on a hot summer day in Texas, ERCOT said one megawatt could only power about 100 homes.
"Our electricity providers are working around the clock to ensure consumers stay cool and safe. ERCOT has not issued any appeals for conservation, but will notify ... stakeholders if system conditions change," ERCOT spokeswoman Leslie Sopko said in an email.
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 102 degree highs forecast for Saturday-Monday would break record highs for those days.
The normal high in Houston, the fourth-largest U.S. city, at this time of year is 94-95 degrees.
In its latest update, ERCOT slightly reduced its forecast for peak demand on Friday to 73,141 MW. That means the grid operator does not expect usage to break Thursday's record until Monday when the peak is projected to reach 75,597 MW.
After Monday, power usage is expected to ease as temperatures return to near normal levels.
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.
Reporting by Scott DiSavino; Editing by Bernadette Baum and Richard Chang