Hot Enough to Melt Records? Ask SDG&E; : Weather: Customer demand hit a new high Monday, but utility officials believe the heat will break before the system does.

As San Diego County continued to sizzle Monday afternoon, residents cranked up their air conditioners and fans, creating a record demand for electrical power.

Inside “Mission Control” at San Diego Gas & Electric Co., workers scurried and computers hummed to meet the record-breaking demand for electrical power--all 3,335 megawatts of it.

“We start to stress the system, but we’ve always been able to supply the power,” said Bernie Alfonso, SDG&E;’s manager of power control.

While Alfonso believes the heat will break before the system does, the challenge is clear: Forecasters say soaring temperatures are not expected to drop until Thursday at the earliest.

In fact, sometime between Thursday and Saturday, a low-pressure system from the Gulf of Alaska is expected to swoop down the Pacific Coast and provide a respite from the scorching heat, easing temperatures by as much as 10 degrees in some areas.

But as forecaster Frank O’Leary pointed out, the relief is only temporary, and for some it may only be a matter of, well, degrees.

“If you’ve got temperatures of 102 that drop to 92, it’s a blessing, but it is still warm,” said O’Leary, who is with the National Weather Service in San Diego.

Throughout San Diego, hot, sunny skies are expected for the next few days, with patches of fog in the morning along the coast. Coastal temperatures are expected to reach 90, while inland they may climb to 104. With the cooler system from the Gulf of Alaska, the heat will then break--temporarily, O’Leary said.

Despite the demand for electricity, which generally peaks in midafternoon, SDG&E; has maintained the 5% to 7% generating reserve required by the state Public Utilities Commission. The reserve ensures that power will be available should an electrical generating plant break down or a transmission wire be severed.

If SDG&E; were to fall below the mandated reserve level, employees at the Mission Valley facility would seek assistance from 40 other Western utilities, including Southern California Edison Corp., the Los Angeles Department of Water and Power and Pacific Gas & Electric Co.

While heavy power consumption regularly produced brownouts and an occasional blackout in Eastern states during the 1970s, SDG&E; has always been able to maintain service in San Diego and southern Orange counties, Alfonso said.

Monday’s peak demand for electricity far exceeded the 2,600 megawatts SDG&E; delivers on a typical summer day. The new high, which was set at 3 p.m., eclipsed the previous record of 3,193 megawatts that was set Aug. 10.

SDG&E; generally has enough electrical generating capacity to meet customer demand on its own. But to control costs, the company instead buys about half its electrical power from other utilities that operate more economical power plants. Generally, about half the power SDG&E; sells to its customers is generated by out-of-town utilities.

On Monday, SDG&E; received about 520 megawatts from its ownership stake in the three nuclear generating plants at San Onofre that are operated by Southern California Edison. SDG&E;’s Encina Power Plant in Carlsbad and the South Bay Power Plant in Chula Vista delivered another 1,730 megawatts. SDG&E; turned on relatively inefficient gas turbines to generate an additional 300 megawatts when the demand for power reached its peak.

The remainder of the power consumed by San Diego County on Monday came from out-of-state utilities. Most of the power was purchased through long-range contracts with utilities in Oregon, Arizona, New Mexico, Canada and Mexico.

SDG&E; also made a spot purchase Monday of 150 megawatts from Public Service of New Mexico. Given the forecast for more hot days--and the economically attractive price offered by the New Mexico utility--SDG&E; will probably make more such purchases, Alfonso said.

SDG&E; officials cite their system’s success as proof that the utility has developed an efficient, economical way to give customers a reliable and affordable source of power.

But SDG&E;’s performance also drew barbs Monday from Beverly Miller, a spokeswoman for Utility Consumers Action Network, a San Diego-based consumers group.

“They don’t have to have such a gold-plated system,” Miller said. “What they should be doing is emphasizing conservation . . . so they wouldn’t have to build (additional generating) facilities. It’s our position that SDG&E; has been terribly negligent in its conservation efforts.”