Texas heatwave to keep testing power grid this week

© Reuters. FILE PHOTO: The sun sets behind power lines above the plains north of Amarillo, Texas, U.S., March 14, 2017. REUTERS/Lucas Jackson

(Reuters) - This week's heatwave will keep testing the Texas power system with record monthly demand expected on Tuesday after less hot weather on Monday kept usage below a new high.

On Friday, power plant failures caused prices to spike over $4,000 per megawatt hour (MWh), forcing the grid operator ask consumers to conserve energy.

The Electric Reliability Council of Texas (ERCOT), which operates the grid for most of the state, said conditions were normal early Tuesday.

AccuWeather forecast high temperatures in Houston, the biggest city in Texas, would reach 94 degrees Fahrenheit (34.4 Celsius) on Tuesday before easing to the low to mid 90s for the rest of the week. That compares with a normal high of 86 in the city at this time of year.

Highs in Houston only hit 93 on Monday, which was below earlier forecasts.

Extreme weather reminds Texans of the 2021 February freeze that left millions without power, water and heat for days during a deadly storm as ERCOT scrambled to prevent a grid collapse after an unusually large amount of generation was shut.

ERCOT projected demand would reach 71,523 megawatts (MW) on Tuesday, breaking the grid's 70,703 MW record for the month of May set on May 9. The all-time peak of 74,820 MW was set in August 2019.

One megawatt can power around 1,000 U.S. homes on a typical day, but only about 200 homes on a hot summer day in Texas.

ERCOT forecast in a report on Monday that continued economic growth would boost peak demand to 77,317 MW this summer. The grid expects to have around 91,392 MW of power resources available to meet usage this summer.

Next-day prices at the ERCOT North hub, which includes Dallas, fell to $79 per MWh for Tuesday from an 11-month high of $246 for Monday.