May 1--Armed with improved transmission and new power plants, Southern California is likely to survive the summer without blackouts as long as there is no unforeseen catastrophe, state agencies and Southern California Edison are predicting.

But the region will rely on voluntary energy shedding by households and businesses to maintain state-required power reserves during worst-case scenarios. And if the region sizzles this summer and suffers some unpredictable event, like a forest fire that takes down major transmission lines, Edison is not ruling out the possibility of rolling blackouts reminiscent of what customers endured during the 2000-01 energy crisis.

Still, Southern California will be in a slightly stronger power position this summer than last, when the Inland region experienced one rotating outage in August resulting from a transmission circuit failure, according to the California Energy Commission and the Independent System Operator, the state agencies in charge of making energy forecasts.

Even though demand for electricity has surged in the past year, it has been more than offset by transmission expansion and new power plants, including the giant Mountainview plant in Redlands, said California Energy Commission Chairman Joe Desmond.

Also, following a wet winter, California's hydroelectric power supply is above normal. And this year, unlike last, the state also can count on a plentiful hydroelectric supply it can import from the Northwest.

"We are certainly better off this year than last year and last year was an improvement on 2004," said Desmond.

Still, state officials say Southern California's power situation is shakier than in the north because the southern region is much more dependent on imports and could fail to meet reserve requirements if it does not find a way to build another 1,200 megawatts of generation over the next three years.

Pedro Pizzaro, Southern California Edison's senior vice president of procurement, said the region's power supplies are "adequate but tight."

"We are not in a position where we have infinite insurance by any means," he said, noting that he wants Edison customers to continue to be mindful of a need for energy conservation.

Forecasters say the most significant variable in determining summer power demand is the weather. This year forecasters expect a normal summer on the coast but higher than normal temperatures inland, which has become an increasingly large part of the utility's business, said Pizzaro.

If there is a combination of above-average heat, transmission congestion and power plant outages this summer, Southern California will meet its power reserve requirements by relying on demand response programs, particularly those that cut off air conditioning to homes and interrupt service to large users like industrial plants.

Without those voluntary programs, the California Energy Commission says Southern California would fall short of the 7 percent operating power reserve required by the state from July through September.

In September, traditionally Southern California's warmest month, the California Energy Commission predicts the operating reserve would fall to 2.5 percent under its worst-case scenario without the prearranged customer cutbacks. Such scenarios occur about once every decade.

Lynda Ziegler, Southern California Edison's senior vice president of customer service, said the company is strongly promoting its "summer discount plan" that allows households to save up to $200 in discounted electricity during the summer by letting the utility put a device on central air-conditioning units that will shut off the cooling at pre-agreed intervals during power emergencies.

Ziegler said there are about 157,000 Edison households on the program, representing a potential savings of 350 megawatts during a power emergency, and Edison is aiming to add another 60,000 households by the end of summer.

Another key program, Ziegler said, consists of 460 large customers, such as manufacturing plants, that in return for a lower electric rate agree to cut off power when called upon. This "interruptible" program is not growing as fast as the air- conditioning reduction program, she said, but can save the utility 600 megawatts of capacity in a pinch.

One megawatt of power is enough to serve 650 average homes, according to Edison.

David Wright, general manager for Riverside's public utility, said that city also believes that even if this summer is extra hot , it will have a sufficient power supply. He said the city's power plants can provide 20 percent of its customers' electricity demand on the hottest summer day and extra power purchases have been arranged.

Also, Wright said that Riverside, like Edison, has been providing rebates to encourage customers to purchase energy -- efficient appliances with the goal of "shaving off" peak power demand, minimizing the need to buy more power or build more plants.

While Southern California's power supply has improved considerably since the statewide crisis of 2000-'01, the power industry, utilities and state agencies agree that future summers will pose a challenge as the region's antiquated power plants suffer recurrent breakdowns or are taken out of service.

"We are not in a position where we should relax. While this summer looks ok, the rapid growth in the population and the economy coupled with global climate changes means we will have to modernize our power system and do it quickly," said Jan Smutny-Jones, executive director of the Independent Energy Producers Association.

Jones said the state has licensed enough projects, which include construction of cleaner and more efficient modern plants and the modernization and repowering of older ones, to produce up to 8,000 megawatts of new power.

However, he said private generating firms cannot get financing to build the plants without long-term contracts from the major utilities to buy the power produced.

Southern California Edison has refused to provide long-term power contracts unless responsibility for paying for the contracts encompasses not only Edison's customers but companies and households within Edison's service territory who choose to buy power elsewhere and municipalities who may leave Edison to establish their own power utilities.

The Public Utilities Commission has received several proposals for allocating the cost of the new power contracts, including a proposal jointly supported by Edison, Pacific Gas & Electric Co., two energy generators and The Utility Reform Network, a California consumer advocacy group.

Pizzaro said he expects that in June or July the PUC will adopt a plan. The issue needs to be resolved promptly, he said, for new power plants to be built in time to fill a power gap in Southern California that otherwise would develop by 2009.

He said new power plants in Southern California are the only feasible solution since it would take longer to build transmission lines to import more power and demand response programs can't be expanded much further.