Electricity supply to get jolt as summer approaches.

A resurgent economy and a drought in the Western states are combining to squeeze California's electricity supplies as the state enters the crucial summer months.

While rolling blackouts or other emergency measures remain unlikely, power industry and state officials say the situation is the most precarious it's been since the power crisis three years ago. A warm summer could force more frequent use of mandatory conservation measures.

"Our reserve cushion is much smaller than we expected and much smaller than we would like," said Suzanne Garfield, spokeswoman for the California Energy Commission, which released a report earlier this month warning of tight energy supplies this summer. "A single widespread heat wave could tip us over the edge."

To help meet increased demand and ward off a possible crisis, several mothballed generating plants are in the process of being restarted and work is being speeded up to improve several electricity transmission bottlenecks.

Nonetheless, vital power supplies remain at the mercy of the weather. Private and government forecasters are projecting a warmer and drier summer than normal this year in California and throughout most of the Western states, which would raise demand levels.

Factoring into the energy equation is a more robust economy. According to the California Independent System Operator, the managers of the state's electricity grid, demand is tip 4 percent over last year, as factories and other businesses increase their output. Forecasts made late last year anticipated demand growth in the 2 percent range. That represents a difference of nearly 1,000 megawatts, or the amount of energy generated at two medium-capacity power plants.

What's more, parts of the state experiencing the most rapid population and industrial growth are in the warm interiors that use the most power in summer months, especially the Inland Empire and the Central Valley. "We have an influx of new customers this year in the eastern area of our service territory, which is the service area that experiences the hottest temperatures," said Ronald Nunnally, director of federal regulation and contracts for Southern California Edison Co.

Hydro crunch

Meanwhile, the state's hydroelectric power supplies are expected to be considerably smaller this year, due to lower-than-normal precipitation this winter in California, the Pacific Northwest and the Colorado River basin. Last week, new measurements came out showing the snowpack at just 48 percent of normal levels in the Sierra Nevada, which would mean much less runoff into dams and reservoirs. That would result in a 15 percent to 20 percent decrease in the state's hydroelectric power supplies.

Locally, the Los Angeles Department of Water & Power gets 10 percent of its power from hydroelectric supplies, while Southern California Edison gets between 5 percent and 10 percent. Some of the hydroelectric power comes from Hoover Dam near Las Vegas. That dam is at record low levels from seven years of drought along the Colorado.

"We're expecting a significant cut in our Hoover Dam allocation this summer," said Henry Martinez, chief operating officer for the DWP's power system.

But Martinez said that lost power will be offset by additional power plants coming online in the L.A. area. Last month, the DWP restarted its Valley Generating Station in Sunland, which is generating about 530 megawatts of power. Martinez said the DWP has also added about 300 megawatts of peaker units that can be turned on at times of peak demand (usually in the late afternoon of hot days).

Martinez said the DWP can turn on those peaker plants to generate excess energy that could be transmitted to other parts of the state facing supply shortages. However, as of last week, the DWP has not been asked to do so.

"If we're asked to do this, we're going to take extra precautions to make sure we recover our costs," he said.

The DWP did not receive full payment for power it sold to the state during the height of the 2001 power crisis.

Likewise, officials with the California Independent System Operator have entered into an agreement with Reliant Energy Co. to restart two mothballed generators in the San Bernardino area. These should bring in an additional 600 megawatts.

Repairs are in progress on a vital north-south transmission line network known as "Path 15." That network has overloaded frequently and in 2001 was a major cause of the rolling blackouts in the Bay Area. When the repairs are completed this fall, capacity along Path 15 should be boosted by about one third.

Upgrades are under way on a Tehachapi Mountains transmission line that's a vital conduit for electricity into Southern California.

But other expansions and upgrades to the transmission grid--including several in the San Diego area that would allow access to Mexican power plants--have stalled as opposition from local residents has mounted. Some residents fear a cancer risk from electromagnetic radiation near high-voltage power lines.

In any event, few of these repairs will be finished in time for the peak demand months of July, August and September.

"For us, September is the most critical month," Garfield said. "That's when we get the combination of hot temperatures and low water supplies."