California’s Energy Supplies Might Dwindle After a Plentiful Winter

California will have ample electricity supplies this winter but could develop shortages next summer if enough bad luck arrives in the form of high temperatures, low hydroelectricity production and power-plant retirements, according to the state grid operator.

Since the energy shortages during the 2000-01 crisis, which led to blackouts on seven days, new power plants capable of generating nearly 9,000 megawatts have kept the electricity flowing.

The lights are expected to stay on this winter, defined as November to April, with power reserves running between 34% and 41%, the California Independent System Operator said in a report released late Friday.

Cal-ISO, which operates the power grid for about 75% of the state, declares a power emergency when reserves fall below 7%.

Problems during the winter could arise in such places as the Humboldt County area and the San Francisco peninsula in Pacific Gas & Electric Co. territory, which feature high winter use, old generators and limited ability to import electricity from other parts of the state, Cal-ISO said.

The picture darkens as early as next summer, Cal-ISO said, if demand is robust because of high temperatures and better-than-expected economic growth coupled with the shutdown of certain power plants and low production from hydroelectric dams.

“These are things that we don’t have control over,” Cal-ISO spokesman Gregg Fishman said.

Under Cal-ISO’s worst-case forecast, reserves shrink to 7.6% next summer and fall as far as 4.9% in summer 2008. The base forecast, which looks for lower demand and high supplies: Reserves are expected to be 12.9% next summer and 9.7% in summer 2008.