Bay Area Heat Wave Strains Power Grid

Tens of thousands of consumers and businesses in the San Francisco Bay Area endured rolling electricity blackouts Wednesday because the area’s electricity grid was unable to handle soaring demand brought about by record 100-plus weather.

High temperatures sent electricity use spiking across California, leading state power officials to declare a Stage 1 power emergency, which means that power reserves fell below 7%. In a Stage 1 emergency, consumers are asked to voluntarily reduce electricity consumption as much as possible.

But the San Francisco area suffered unusual difficulties caused by mechanical problems in at least two Bay Area power plants at a time when temperatures were reaching highs not seen in decades. San Francisco sweltered at 103 and San Jose hit 109 Wednesday afternoon.

The Bay Area’s power problems underscore California’s precarious electricity situation this summer.

Energy officials have warned that although the state has sufficient generating capacity to keep lights burning and air conditioners humming if this is a normal summer, there could be energy shortages and rolling blackouts if it’s a hot summer like the one in 1998. That’s because recent growth in the state’s population and economy have caused electricity demand to increase about 2% a year, but new power-generating facilities will not come on line until 2001.

The California Independent System Operator, the nonprofit agency that manages most of the electricity flow around the state, is urging conservation and has identified businesses that are willing to conserve power for a price.

Each of the big investor-owned utilities has its own program under which large industrial and commercial customers can get reduced rates in exchange for agreeing to have their power interrupted during a Stage 2 emergency, when reserves fall below 5%. A Stage 3 emergency, which has never been declared on a statewide basis in California, means reserves have fallen below 1.5% and involuntary power interruptions may begin.

Pacific Gas & Electric Co. began cutting power to blocks of customers at 1:22 p.m. Wednesday in areas as far south as San Jose and as far east as Antioch.

Each block of 35,000 customers was in the dark for between 60 minutes and 90 minutes, then the blackout was shifted to another block of customers, said Tom Collins, spokesman for the San Francisco-based utility. Collins said about 97,000 customers were affected by the blackout, which ended about 4:30 p.m. as demand began to taper off.

The San Francisco utility took the action on orders from the California Independent System Operator, or Cal-ISO, which was created to run the state’s long-distance electricity transmission system as part of the 1998 deregulation of the California electricity industry.

“In the Bay Area, we have been having problems all day with voltage,” said Patrick Dorinson, a spokesman for Cal-ISO. “This was a decision to protect the integrity of the system.”

Jon Tremayne, a spokesman for Pacific Gas & Electric, said the blocks of affected customers, representing about 100 megawatts of usage, were scattered throughout the Bay Area, so that each city in the region had some affected customers. However, he could not say whether any major businesses experienced outages.

Communities around the Bay Area were cautioned to voluntarily reduce their power consumption, but officials in Fremont, on the southeastern edge of the bay, and in San Jose said they had not heard of any power outages in their areas.

Technology companies in Silicon Valley, including Sun Microsystems, Yahoo, Cisco Systems, Excite@Home and Xerox, said they were all a bit warm, with their air conditioning adjusted to comply with the suggested guidelines. But none reported service or production interruptions.

“In Palo Alto, we’ve been asked by the city government to power down or be conservative with our use of power,” said Emily Fox, a spokeswoman for Hewlett-Packard. “In Cupertino, our site is really reducing power to the point of turning off a lot more lights and turning off systems that are not essential.”

Intel, the leading semiconductor manufacturer, was taking similar precautions. “The lights have gone down,” Intel spokesman Tom Waldrop said. “But there is no impact on the factories.” The company operates a research and development fabrication plant at its Santa Clara headquarters.