Heavy rains cut off power for more than 122,000 Houston-area customers early Monday, and real-time wholesale prices swung from less than $16/MWh to more than $73/MWh, according to distributors and the Electric Reliability Council of Texas.
Rainfall totals ranging from 10 to 20 inches were measured in southeast Texas on Monday morning, according to The Weather Channel, causing widespread flash flooding and bringing the Houston area to a virtual standstill.
Newly elected Mayor Sylvester Turner canceled a planned "State of the City" speech Monday morning and urged all citizens to stay home, if possible. Most school systems were closed for the day.
Several sections of major highways and thoroughfares were shut down due to high water, and a number of bayous overflowed their banks.
Houston's two main international airports had 663 canceled and 153 delayed departures and arrivals on Monday, 40% of the scheduled air traffic.
At the height of the storm, about 8:30 am CDT (1330 GMT), ERCOT Houston Hub real-time power prices dipped from about $22.20/MWh to about $15.85/MWh at 9 am, and hovered around $20/MWh for the next few hours before spiking to about $73.75/MWh at 11:30 am CDT, on the heels of an ERCOT grid operations advisory that physical responsive capability had dipped below 3,000 MW.
The reasons for the low physical capability likely included the North DC tie being made unavailable at 8 am through midnight Friday because of a planned outage, and ERCOT seeing a sudden loss of 768 MW of generation at around 11:30 pm CDT Sunday.
Alicia Dixon, CenterPoint Energy spokeswoman, the Houston area's transmission and distribution service provider, said that as of 1:50 pm CDT, 49,812 customers remained without power, scattered over a wide portion of the metropolitan area.
"It's proving challenging to get to some areas," Dixon said. "We are asking customers to be prepared for some delays."
