ERCOT: Texas power grid ‘healthy’ for fall, winter after summer strain

By: Bob Sechler |

What doesn’t kill you makes you stronger might be a fitting maxim for the state’s main electricity grid as summer winds down.

The grid — strained to near capacity over the past few months by triple-digit temperatures and record demand for electricity — is in good shape for the fall and winter after enduring the test, according to a new report.

“Our assessments show a healthy amount of operating reserves heading into the fall season,” said Pete Warnken, manager of resource adequacy for the Electric Reliability Council of Texas, which oversees the power grid and is commonly known as ERCOT.

The prognosis marks an improvement from ERCOT’s initial pre-summer assessment early this year, when it warned of an exceptionally slim operating cushion between maximum summer generating capacity and estimates for peak electricity demand.

At the time, ERCOT officials expressed confidence in the reliability of the grid but also cautioned that so-called “load-control measures” — including the possibility of rolling blackouts — might be needed if summer conditions turned out to be significantly hotter than normal or otherwise extreme.

Peak demand for electricity in the state ended up setting a record of 73,308 megawatts between 4 p.m. and 5 p.m. on July 19, coming perilously close to eclipsing generation capacity but not doing so. The situation was improved from ERCOT’s early outlook partly because three power plants that the agency hadn’t expected to be operational for the summer ended up coming online.

This fall, ERCOT is estimating peak demand of 58,619 megawatts and maximum generating capacity of more than 81,700 megawatts.

Factoring in typical plant outages for maintenance and other issues during the season, ERCOT has pegged the grid’s operating reserve cushion at just under 11 percent. It has estimated the operating reserve margin for the winter at about 13.5 percent if conditions are typical.

“We are in good shape for the fall and winter seasons,” Warnken said. Still, he cautioned that “there are certainly scenarios that you can cook up” that would put an unforeseen strain on the grid, such as unusually cold temperatures or an inordinate number of plant outages.

In general, however, he said the state’s deregulated electricity market has worked as it should this summer, with power producers increasing generation to take advantage of high demand.

“We did see plants (becoming) available for the summer to meet demand,” he said, with some postponing scheduled maintenance to keep generating.

“I would say the market performed very well,” Warnken said.

In a preliminary assessment, ERCOT is projecting peak demand of 61,780 megawatts over the coming winter. The record for winter peak demand was set on Jan. 17 this year, when it reached 65,915 megawatts between 7 a.m. and 8 a.m. that day because of extremely cold temperatures, ERCOT said.

About 90 percent of electricity flow in Texas is managed by ERCOT. One megawatt of electricity can power about 200 homes during periods of peak demand, according to ERCOT.

ERCOT: Texas power grid ‘healthy’ for fall, winter after summer strain