ERCOT calls for conservation for seventh time in August

The state's grid operator asked Texans to conserve electricity on Tuesday as some power plants fueled by gas, nuclear power, or coal unexpectedly went offline and wind power generation looked low. It's the seventh such request from the Electric Reliability Council of Texas this month amid intense heat and threats of a power-supply emergency.

So far, the grid has held up, and temperatures even cooled slightly around much of the state this week. ERCOT did not say why the power plants went offline Tuesday, and warned that it may request that customers conserve energy on Wednesday too.

College Station reached 101 just before 5 p.m. Tuesday after snapping a 50-day streak of 100-degree temperatures on Monday. Twice in August the Brazos Valley has set or tied all-time temperatures at 112 degrees, the last time coming on Sunday, just before the cool front passed through the area.

ERCOT asked people to reduce their energy use between 5 p.m. and 9 p.m. Tuesday, hours that are typically the most perilous for the grid because people returning home from work crank down their thermostats while solar power dwindles as the sun sets.

Extreme heat this month has driven demand for power to record levels. Houston tied its hottest day ever on Sunday when temperatures reached 109 degrees. New solar farms have helped meet daytime demand, but forecasts for low wind or gas-, nuclear-or coal-fueled power when the sun sets has caused concern.

If people try to pull more power off the grid than is available, grid infrastructure can be badly damaged. ERCOT can call on reserve power sources and trigger emergency operations to prevent that from happening. A worst-case scenario would bring rolling power outages.

Unlike the rest of the United States, much of Texas is on the ERCOT power grid, which largely stands alone. Operators in a statement said they have been calling on large power users to reduce their consumption and asking other grids to provide what limited help they could.

Residents can conserve energy by turning up thermostats a few degrees and refraining from using large appliances such as washing machines and clothes dryers.

In addition to Tuesday, ERCOT asked residents to conserve power on Aug. 17, 20, 24, 25, 26 and 27.