Power and Transmission Outages Strain California Power Supply

July 15, 2003

FOLSOM, Calif. — California's electricity supplies were stretched Monday by three plant outages and a transmission glitch that occurred when a logging truck drove under a high-voltage power line.

About 1,500 megawatts of power was lost Sunday night when two Northern California power plants tripped off-line, said Stephanie McCorkle, spokeswoman for the Independent System Operator, the manager of the state's electricity grid.

A 750-megawatt power plant in Southern California went off-line a few hours later, McCorkle said.

The outages came on a day when peak electricity use is expected to top 41,500 megawatts because of hot weather throughout the state, she said. A megawatt is approximately enough power for 750 homes.

The state lost some imported power early Monday Bonneville Power Authority officials reduced the amount of power traveling across a major transmission line near the Oregon border after a logging truck drove under the line with its boom raised.

No injuries were reported, said BPA spokesman Ed Mosey. The 4,000-megawatt line was reduced to about 2,900 megawatts, he said. The line was operating at full capacity by around noon.

The ISO asked power plant operators to restrict maintenance until 10 p.m. to avoid any other outages, McCorkle said.

"We do not anticipate a Stage One, but of course, we'd like to see conservation kicking in," she said.

Grid managers call a Stage One power emergency when reserves drop below 7 percent.

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