Power Grid Survives a 3rd Emergency Day

California electricity authorities declared a moderate Stage 2 emergency Wednesday as the state power grid successfully sweated through near-record electricity use during the sixth day of a stubborn heat wave.

Meanwhile, the board of the California Power Exchange, which runs the state’s primary market for wholesale power, on Wednesday asked the Federal Energy Regulatory Commission for permission to cap electricity prices at $350 per megawatt hour in the day-of and day-ahead markets.

The California Independent System Operator, which operates the electricity grid for most of the state and runs a wholesale market of backup emergency power, lowered its price cap to $250 per megawatt-hour Aug. 1 in an attempt to control soaring electricity prices.

Wednesday marked the third Stage 2 emergency in three days and the 13th emergency of the year, compared with only one in 1999 and four in 1998.

Under orders from Cal-ISO, the state’s three big investor-owned utilities on Wednesday afternoon interrupted power to customers representing about 1,500 megawatts, or enough electricity to power nearly 1.5 million homes. These customers--primarily large commercial and industrial users--get cheaper power in exchange for reducing usage when electricity supplies are thin.

Southern California Edison and the other utilities made urgent appeals for customers to use as little electricity as possible today because power demand is expected to remain brisk.

“We can get through this difficult period and possibly avoid a Stage 3 emergency if we all stick together and reduce power use as much as possible,” said Pam Bass, Edison’s senior vice president for customer service.

Cal-ISO declares a Stage 2 emergency when reserves fall below 5%. If reserves were to plunge below 1.5%, an unprecedented Stage 3 would be instituted and rolling blackouts would become likely to prevent a wider and more serious system collapse.

Reserves got as low as 3.9% Wednesday afternoon as electricity usage peaked at 44,457 megawatts, adjusted to include the 1,500 megawatts that were interrupted, in the 75% of the state where the power flow is tended by Cal-ISO. Californians set a power record of 45,884 megawatts on July 12, 1999, on the Cal-ISO grid.

The electricity grid was further strained Wednesday because mechanical breakdowns at overworked power plants removed about 2,122 megawatts of generation, most in Southern California.