By: EDMOND JACOBY - Staff Writer

Jim Detmers, vice president of grid operations for the California ISO, talked about concerns of power blackouts and conservation efforts this coming summer. Don Boomer

SAN DIEGO ---- Customers of San Diego Gas & Electric could face the possibility of rolling blackouts this summer unless efforts to convince them to conserve electricity are successful, representatives of SDG&E and the California Independent System Operator said Monday.

Part of the problem ---- but only part ---- is the 3-in-10 likelihood of hotter than usual temperatures this summer.

"The 30 percent estimate comes from the National Weather Service," said Jim Detmers, vice president of grid operations and interim chief operating officer of the California ISO, the not-for-profit organization that manages the electric transmission lines that shuttle power around the state.

"We've been working with Scripps Oceanographic Institute, and though the work with Scripps isn't complete, it's sort of leaning in the same direction, that it could be hotter than normal," he said.

The higher-heat scenario troubles both the ISO and SDG&E because energy consumption in the San Diego region has been rising sharply.

"Average statewide demand is growing at a rate a little above 3 percent, 3 to 4 percent," Detmers said.

"But in this area, we've got demand growth ranging between 4 and 10 percent, depending on the community," he said.

Part of the growth is related to the growth in housing units, but some is just folks paying less attention to conservation efforts after several years with no blackouts.

"We're trying to make sure that we can hit the demand peaks, even with tight transmission margins; we expect high imports, but the economy is still coming on strong, so we have to get customers to back off demand," he said.

Upgrades to some transmission lines will allow more electricity into SDG&E's distribution network this summer, but last September set a new record for electricity usage ---- 4,065 megawatts on Sept. 10, compared with normal electricity demand between 2,800 and 3,200 mW. A megawatt is enough electricity to power about 1,000 homes.

According to SDG&E Vice President for Electric Transmission and Distribution David Geier, the utility's customers voluntarily cut demand 10 percent, or about 300 mW.

The company has a new power plant coming on line this year near Miramar, and next year expects the Palomar generator to be completed in Escondido, Geier said. A third plant will be completed in South County in 2008.

"But what's happening is, they're retiring older plants for economic reasons and because their air quality is not good," he said.

Detmers estimated the ratio between new plants and closed ones at 10,000 mW to 4,000 mW, leaving a net gain of 6,000 mW statewide since 2001. That is barely enough to keep up with growth in demand, he said.

Contact staff writer Edmond Jacoby at (760) 739-6675 or ejacoby@nctimes.com.

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