Blackout Risk Shifts to California From Texas as Heat Sears West

(Bloomberg) -- The possibility of blackouts is easing in Texas as more power plants returned to service, but risk is rising in California as a dangerous heat wave pushes temperatures into triple digits across western states.

The Texas grid operator estimates available capacity will rise to 75 gigawatts this afternoon, up nearly 6% from Tuesday as plants that were down for repairs come back on line. Demand is forecast to peak at nearly 70 gigawatts, little changed from Tuesday, as temperatures in much of Texas climb above 95 degrees Fahrenheit (35 Celsius).

In California, the heat wave is only beginning. Sacramento could reach 110 Thursday and Friday, sending demand for power surging. California officials have already warned of possible shortfalls.

“It is going to be historic considering some of the records and duration of it lasting over a week,” Bob Oravec, a senior branch forecaster at the U.S. Weather Prediction Center, said of the heat wave.

California’s grid operators have warned the biggest power crunch could be Thursday. While the state relies on electricity from neighboring states during heat waves, this week’s heat is expected to stretch clear to the Canadian border, limiting imports, according to the California Independent System Operator, which manages most of the state’s power grid.

The scorching weather marks the first heat-related stress tests of the year for U.S. electric grids as a historic drought grips the western half of the nation. It comes almost a year after California endured rolling blackouts during a heat wave last summer.

Texas supplies tightened after plants with as much as 12.2 gigawatts of generating capacity, enough to run about 2.4 million homes, unexpectedly were down for repairs in recent days. By late Tuesday, that figure had fallen to 10.6 gigawatts. About two-thirds of those out of service are natural gas, coal and nuclear plants. The rest are wind and solar, the grid operator said.

The system had about 4.7 gigawatts of power reserves as of 10:56 a.m. local time. Ercot said it would call the first stage of a grid emergency should reserves fall below 2.3 gigawatts and would start rolling blackouts if they fell below 1 gigawatt.

One thing that might cool temperatures along the Texas coast is rain from a potential tropical system taking shape in the southern Gulf of Mexico.“Maybe by Monday a cold front will push down from the north,” said Oravec. “Until then it’s going to be hot.”

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