Houston — As the Electric Reliability Council of Texas' power demand neared another record for peakload Tuesday afternoon and ERCOT called for energy conservation, real-time wholesale power prices, including congestion and price adders, topped $9,000/MWh.
As a heat wave continued to grip the state, ERCOT set a record of 74,531 MW Monday, and real-time prices spent two hours and 15 minutes above $1,000/MWh, hitting as high as $6,537.45/MWh. Real-time prices spent another 2.5 hours between $100 and $999/MWh Monday.
High temperatures hit 100 degrees Fahrenheit in Houston Monday and 101 in Dallas and San Antonio, according to CustomWeather. They were forecast to hit 102 F in Dallas and San Antonio Tuesday and 99 F in Houston.
Around 2 pm CDT Tuesday, ERCOT forecast load to peak at 75,586 MW, but by 4:15 pm, that forecast had fallen to 74,552 MW, which still would have been a record. As of 4:30 pm CDT, ERCOT reported current system load at 74,181 MW. ERCOT's previous record, set July 19, 2018, was 73,473 MW.
Systemwide prices, including scarcity adders and congestion, topped $100/MWh at 3 pm CDT Tuesday, settling at $216.09/MWh for the first 15 minutes. By 2 pm, the systemwide average was $2,004.19/MWh, and it stayed above that through at least 4:15 pm CDT - above $9,000/MWh for the period after 3:30 pm.
A weather system was forecast to move through much of the state Wednesday, limiting highs in Dallas and Houston to the low to mid-90s, but San Antonio was still expected to hit 100 F.
Around 3:15 pm Tuesday, ERCOT declared an Energy Emergency Alert, as physical reserves had fallen below 2,300 MW, and called for voluntary energy conservation between 3 pm and 7 pm CDT. The EEA allows ERCOT to "call on all available power supplies, including power from other grids, if available," according to an ERCOT EEA document.
ERCOT made it through the summer of 2018, which was hotter through June and July, without having to declare an EEA.
The Public Utility Commission of Texas also called on residents to limit their electricity usage.
"When the energy demands of our state's steadily growing population and booming economy intersect with hot summer temperatures, the supply of power can get a little tight, so we're calling on Texans to help moderate demand for electricity with a few simple choices during the late afternoon hours this week," PUC Chairman DeAnn Walker said in a media release.
Asked to speculate about the long-term effects of this week's heat wave and power market behavior, Campbell Faulkner, senior vice president at OTC Global Holdings, an interdealer commodities broker, said that if the market has to reach the next level of Energy Emergency Alert, ERCOT can reduce system demand by interrupting power for large industrial customers who have contractually agreed for such contingencies.
If such an event happens, Faulkner said that "in the long term the market will likely move to a capacity market structure."
"This is due to the fact that ERCOT has not replaced a lot of the coal fleet retirements with large gas-fired base load [generation] due to financing costs and variability [historical] of natural gas [prices] as compared to coal/nuke fleet," Faulkner said in an email Tuesday. "Today there is concern about rotating outages and automatic load shed if the total load is not reduced. ... Over the past two days the variability in grid frequency shows that the market and generators are struggling to maintain grid tie and voltage."
-- Mark Watson, email@example.com
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