With the possibility of record heat back in the forecast, the Electric Reliability Council of Texas has issued a weather watch for the rest of the workweek as it eyes the possibility of more grid-threatening demand for electricity.
It comes as the state’s main grid operator is again facing unexpected outages of gas- and coal-fired power plants, high temperatures are increasing Texans’ appetite for air conditioning and forecasts suggest too little wind power will be available to get through the evening hours when supply is tightest.
The last weather watch — an alert ERCOT uses to tell Texans they should be aware of conditions — came amid a two-week period in which it asked Texans to conserve power eight times.
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No request for conservation had been issued by Wednesday afternoon, but ERCOT’s demand forecast showed the supply of power would narrow starting about 7 p.m. and the pattern would continue through Friday.
The grid operator’s data showed about 6,000 megawatts of so-called thermal generation had been removed from the grid due to outages at gas and coal plants Wednesday afternoon. That’s about 1,000 megawatts more than ERCOT says the the grid is prepared to handle. Wind power was forecast to come in between 3,000 and 4,000 megawatts, also on the low end of what ERCOT expects.
Generation from gas- and coal-powered plants and wind turbines becomes vital from 7 to 9 p.m. when demand is high and the cushion solar power provides throughout the day starts to drop rapidly at sundown.
Plant breakdowns
ERCOT’s latest unplanned outage report showed gas and coal plants are continuing to deal with breakdowns, probably from running at full capacity to keep up with this summer’s rising demand. The report is issued with a lag of about three days so it doesn’t capture the situation in real time. But it does give a peek into plant conditions across the state.
It showed outages at coal and gas plants weren’t as extreme Wednesday as they had been when the grid was tightest in the second half of August. But there were still dozens of generating unit outages statewide.
Among them, Lake Hubbard Power Plant in Sunnyvale logged a 392 megawatt gas-fired unit’s outage in June. It’s expected to continue until the end of the month.
Handley Generating Station in Fort Worth reported a natural gas plant with a 375 megawatt outage that began Aug. 31. It was expected to be repaired Wednesday.
The coal-fired W.A. Parish plant, which was built in the late 1970s, reported a 577 megawatt outage beginning Sept. 3, it too, estimated would be fixed by Wednesday. The aging plant, which provides power to Houston, regularly is coming on and off line because of needed repairs.
Plants’ estimated return dates are bests guesses, with some needing more time and others finishing repairs days or weeks ahead of the date they reported.
Out of balance
Many of the state’s gas- and coal-powered plants are 30 and 40 years old. ERCOT CEO Pablo Vegas last week told his board capacity would continue to tighten if the state’s power generators don’t make investments in bringing newer gas, coal and nuclear plants online.
He has called the Texas grid’s current fuel mix “unbalanced” as solar, wind and battery power continue coming online at a faster rate than “dispatchable” power, the industry term referring to sources that can be turned on and off.
Texas came uncomfortably close to rolling blackouts last month when demand for power pushed the system to the brink of requiring forced outages to keep it from failing, Vegas said last week. Only robust response to requests for Texans to conserve, he said, headed off emergency conditions.
Amid such issues, the grid that serves about 90 percent of the state has seen demand jump during this summer’s heat. So far, ERCOT has set 10 all-time peak demand records this year.
ERCOT said Monday’s peak demand set a September record of 78,459 megawatts, topping the previous September peak record set in 2021. The current all-time peak demand record of 85,435 megawatts was set Aug. 10. It takes 1 megawatt to power about 200 Texas homes on a hot summer day.
ERCOT said this week’s weather watch is due to forecasted higher temperatures, higher electrical demand and lower power reserves. It continues through Friday.
Read More: ERCOT issues another weather watch as Texas grid faces more stress