ERCOT Prepares Texas Grid for Record Summer Demand with Temporary Generators

Bracing for record-high demand this summer, the Texas grid operator is setting up temporary generators at San Antonio substations as part of its plan to prevent a statewide transmission meltdown.

The Electric Reliability Council of Texas said its latest forecast calls for this summer’s peak demand to reach 87.5 gigawatts — 2 gigawatts higher than the current record.

ERCOT President and CEO Pablo Vegas said the grid he oversees is ready to handle it.

RELATED: ERCOT anticipates 'significant increase' in upcoming demand forecast

“The state of the grid is strong,” he told board members Tuesday. “It is as reliable as it has ever been, and it is as ready for the challenges of extreme weather that we have ever experienced. And so I feel confident that we are ready for this upcoming summer season.”

While ERCOT anticipates the state’s power plants will produce enough capacity to meet the demand, the state’s sagging transmission infrastructure could pose challenges moving that power to where it’s needed when it’s needed. A problematic circuit that makes a loop around San Antonio could cause cascading outages across the state if overloaded.

That’s why ERCOT is shelling out more than $110 million of its ratepayer-funded budget to tap a temporary generator fleet from Houston for about 450 megawatts and to keep an aging CPS Energy natural gas plant open past its prime — adding another 400 megawatts of power in the troubled area.

The old plant won’t be fixed up in time to operate this summer, but some of the generators will be ready to go in a couple weeks, Vegas announced.

It’s part of ERCOT’s plan to keep the lines from being overburdened, especially when plentiful power from South Texas wind farms and batteries is needed in North Texas, where generation capacity hasn’t kept up with increasing demand. The location of the plant, Unit 3 at Braunig Power Station, means that ERCOT can use it — along with the 15 generators, tied to nine key substations along the problematic circuit — to reduce the number of electrons zipping across the troubled power lines at times of high demand.

RELATED: At ERCOT’s request, CPS spending $150M to speed up new transmission lines

CPS already is working on a long-term fix for the transmission challenges — building out expanded power lines. At ERCOT’s request, they’ve speeded up the timeline to get the line upgrades completed.

‘Mobile’ generators

The temporary generator fleet has a contentious past. It was originally under the control of Houston electricity and natural gas provider CenterPoint Energy as part of an $800 million contract with owner LifeCyle Power. It was intended to provide backup power to keep Houston powered amid severe weather.

But when Hurricane Beryl tore through Houston, knocking out power for days, most of the generators were never deployed. That’s because 15 of the 20 contracted machines take several days to assemble and need special permits — not well suited for sudden outages caused by a storm, despite being billed as “mobile generators” by CenterPoint.

Five of the generators already have been moved to San Antonio and four were fully assembled as of Tuesday. A second set of five were expected to arrive Wednesday.

“What the contract provides for is bringing roughly five generators online into the San Antonio area every 31 days, with the first generators beginning operation by the early part of July,” Vegas said.

Once they’re assembled, the generators can be fired up quickly to provide emergency backup services to support the transmission infrastructure while permanent line upgrades are ongoing.

The fleet is contracted until March 31, 2027, but can exit San Antonio sooner if the transmission expansion finishes up sooner. The contracted cost, to be shared by ratepayers across Texas, is $54 million.

Braunig’s budget

The costs of efforts to keep Braunig 3 running continue to rise as ERCOT works to get the plant operational in time for winter. It had hoped to have it ready for the summer, but the repairs — as CPS warned — were too extensive.

CPS had planned to retire the plant in March, but ERCOT stepped in to keep it open because of the transmission issues. With another $10 million in costs announced Tuesday, the total to get Braunig Unit 3 operational now comes to about $59 million.

The state’s fleet of natural gas plants is aging faster than new ones are opening — something the state has attempted to remedy with low-interest loans through the Texas Energy Fund. But supply chain issues are dampening the speed at which new natural gas plants can be built nationwide even as demand is accelerating at record speeds, fueled by data center growth.

ERCOT has lost a net of 366 megawatts of natural gas power since last summer. Meanwhile, 3,800 megawatts of batteries and 5,400 of solar power have come online — well above the would-be losses of Braunig’s 400 megawatts if it shuttered as planned. Even so, ERCOT plans to continue with plans to bring it back online.

“There’s been a lot of changes and additions on the grid that have happened over the last year and a half,” Vegas told board members. “Our teams factor those known additions coming onto the grid … and still justified, cost effectively, to keep that unit running until the transmission solution has been built.”

Vegas’ remarks were likely pointed at criticisms from grid expert and author of a popular energy politics newsletter, Doug Lewin, who has called the expenses costly and unnecessary.

Lewin said the new batteries that came online in the last year are in locations that could ease the transmission issues. Batteries can act as shock absorbers, holding on the electrons like a sponge if a line is at risk of being overcrowded.

The 55-year-old plant would be powered up only in case of an emergency — but steam-turbine power plants of that age can take eight to 24 hours or even more to heat up in order to operate.

Vegas said the costs to keep Braunig up and running are less than the costs of managing a transmission emergency without its power.

Summer ahead

If Texas power users set the new demand record ERCOT has forecast, it likely would come in August.

“Part of that’s due to large load growth and just the general economic growth,” said Dan Woodfin, ERCOT’s vice president of system operations. “Part of that’s also because of higher temperatures.”

The current demand record is about 85.5 gigawatts. It was set in August 2023.

ERCOT’s August reliability assessment says the likelihood it will have to resort to rolling outages during the month’s peak heat is less than 1% this summer — a big drop from the 12% risk for brownouts it calculated last August. The drop is largely thanks to the influx of batteries.

“That assumes that a lot of things happen in the way they’re supposed to happen, including large loads that are flexible, that are price sensitive, turning off at the right time of day,” Woodfin said of the assessment. “It assumes that batteries charge and then discharge and manage their state of charge so that they’re available during the tighter time frames.”

Those riskier periods come at 9 p.m., when the state loses its big cushion from solar power because the sun is down.

Woodfin said ERCOT also is keeping an eye on line congestion outside of the well-known points in South Texas.

“We don’t see any wide area of concern,” he said of this summer, but that congestion-related planning will be top of mind in the coming summers. “We have areas where we have lots of large load growth. Even though we’ve got a great transmission plan to help serve all that load, there may be localized areas where the load goes faster than the transmission can get there.”