California Blackout Threat Eases Slightly

It looks as if the worst strain on the California power grid is over for this week, a spokesman for the California Independent System Operator said recently.

A Stage 1 power emergency remained in effect until 8 p.m. PDT July 25 but once that is removed, no more power emergencies are expected for the remainder of the week, said Lori O'Donley of the Cal ISO.

A cooling trend seen for the rest of the week is likely to spare the power grid system from having a crisis, another Cal ISO representative added, but he offered a caveat.

"If everything holds together, we will be all right. But if we have a major contingency like a plant going off or losing transmission, then we will have a problem," said Gregg Fishman, spokesman for the Cal ISO.

No major outages are reported in the state and the 62,000 customers without power on July 25 were dark as a result neighborhood transformers overheating.

Southern California Edison, which has 4.7 million residential and business customers in an 11-county area of Southern California, has its own weather stations in its service area. Forecasters for SCE say they are seeing a cooling trend, said Gil Alexander, So Cal Ed spokesman.

"We are seeing a cooling trend," said Alexander. "It is very gradual. It began (Monday) night but it did not prevent another record."

Alexander referred to So Cal Ed setting yet another peak demand mark on July 25 while most of the state's other major utilities set records either the previous day or July 22.

The temperatures will go down gradually, but demand may not go down as quickly because it is not getting cool enough during the night to allow buildings to lose their warmth, Alexander said.

"Residual building heat is a part of this story," Alexander said. "You go through a heat wave and structures don't cool off as they usually do at night so air conditioners kick on earlier the next day and run longer and harder.

In downtown Los Angeles, the nighttime low of the evening of July 23 was 75 degrees Fahrenheit, 10 F higher than the norm.

Cal ISO declared a Stage 1 power emergency on the power grid early in the afternoon. It called the first Stage 2 of the summer on Monday but did not have to resort to that measure on July 25.

In a Stage 1 situation, the ISO calls for voluntary conservation to ease the strain on the system.

In Stage 2, the business customers involved volunteer to cut power during emergencies in exchange for lower utility rates.

July 25 demand did not break a record for usage set on July 24. The peak load on the power grid the next day was 49,762 megawatts at 3:18 p.m., not surpassing the July 24 peak of 50,270 megawatts.

The grid manager operates a three-stage emergency program beginning with appeals for voluntary conservation in Stage 1, interrupting business customers in Stage 2, and ordering blackouts in a Stage 3.

The last Stage 3 in California was declared in May 2001.