PUMPED UP FOR POWER CASTAIC PLANT CHARGED WITH HELPING MEET L.A.'S ELECTRICITY NEEDS.

Byline: Charles F. Bostwick Staff Writer

CASTAIC - When the thermometer hits 102 in Woodland Hills and residents are cranking up their air conditioners, that's when the Los Angeles Department of Water and Power's Castaic Power Plant gets the call.

Using water flowing through the California Aqueduct, the plant can power up one of its six 275,000-horsepower turbines - each capable of lighting 240,000 homes.

Then at night, when the demand for electricity goes down, the generators turn into giant electric motors and the turbines into pumps. They push the water back up through a 1,000-foot-long, 30-foot-diameter tunnel, for use again the next day.

``We become like a giant storage battery in the system,'' says plant Superintendent Tom Lanski, a bearded, talkative man who has worked at the Castaic plant for 20 years and says he takes his job seriously: ``Electricity isn't a luxury.''

Tucked in a steep canyon 10 miles north of Valencia, at the northwestern tip of the state's Castaic Lake reservoir, the Castaic plant is one of California's few pump-storage plants: creating power during the day when demand is highest, then pumping the water uphill at night for reuse.

As millions of Californians served by Southern California Edison and Pacific Gas and Electric wonder whether summer will bring rolling blackouts, Castaic is one of the DWP plants that let Los Angeles export hundreds of megawatts to fill shortages elsewhere.

At full power - feeding 8 million gallons of water a minute to its six turbines - the plant can produce nearly 1,200 megawatts of electricity for nearly 12 hours. That's about one-fifth of the electricity the 3.8 million Angelenos use on the hottest day.

First operational in 1973, the plant was originally designed to be paired with a nuclear power plant in Malibu. The pump-storage plant would have used the nuclear-generated electricity at night, when Angelenos were asleep, and their lights, television sets and factory machinery mostly turned off.

But the nuclear plant was never built, so the DWP uses its nighttime electricity from its coal plants and other sources to run the generators and turbines.

And during the day, the plant helps the DWP meet the city's needs when electrical use is the highest, and when other plants must shut down for maintenance or repairs.

As Californians have learned since last summer, electricity needs vary throughout the day. They are highest between 5 and 7 p.m., lowest before dawn.

On March 27, for example, California was using more than 28,000 megawatts at 7 p.m., but only 19,400 megawatts at 3 a.m.

While a steam-powered plant can take hours to turn on, Castaic's turbines can be switched into gear within five minutes. In addition, the plant can provide ``cranking power'' to restart other plants if they are knocked out in a major power failure.

``There's no other resource that comes close to that capability,'' National Hydropower Association President Chris Hocker says of pump-storage plants' quick start-up.

Pump-storage plants, of course, have disadvantages. The main one is that it takes energy to move the water back uphill - more energy than the water flowing downhill can create. For every 70 kilowatts of power Castaic puts out, it takes 100 watts to move the water uphill to Pyramid Lake.

They are also far more expensive than a natural gas-fired power plant, and they need a suitable site: a lower reservoir, a suitable elevation gain, and a place for an upper reservoir.

In Castaic's case, the upper reservoir is Pyramid Lake, fed by the California Aqueduct. The lower reservoir is the Elderberry Lake forebay of Castaic Lake.

Because the power plant uses so much water - it can cause the lower lake level to rise and fall as much as 25 feet in a day - Elderberry Lake is separated from the main Castaic Lake by its own dam. That prevents the fluctuations from being felt by boaters and anglers and water-skiers.

The water comes out of Pyramid Lake and down the 30-foot-diameter Angeles Tunnel, bored through rock, to six 13-foot pipes - called penstocks - that emerge from the hillside above the plant.

Each penstock feeds a column of water to its own turbine. The water then gushes out of the plant into the tailrace leading to Elderberry Lake.

``We run about 6,000 acre-feet of water through the units in a day - about 5,000 megawatt-hours - which is an average day for a weekday,'' plant engineer Kent Cotterell said. ``We run more in the summer, substantially.''

The United States has fewer than 30 pump-storage plants, the biggest a 2,100-megawatt plant completed at a cost of $1.7 billion in 1985 in Virginia.

The federal government has approved the construction of three in the past 10 years, but none has been built - mostly because of the difficulty of getting financing for such a costly project under the uncertainty of deregulation, said Hocker of the hydropower association.

``I believe it is very likely there will be others built in the United States. How many? Probably not very many,'' Hocker said. ``It is a major piece of construction. Here and there there are suitable sites.''

CAPTION(S):

5 photos, map

Photo:

(1) Tom Lanski, superintendent of the DWP's Castaic Power Plant, walks in front of a series of large pipes that carry the water into the plant and also take the water back out.

(2 -- ran in SAC edition only) Plant Control Operator Aaron Westbrook monitors the controls at the plant, which can produce about one-fifth of the electricity that 3.8 million Angelenos use on the hottest day.

(3 -- ran in SAC edition only) Castaic Power Plant Superintendent Tom Lanski stands near a turbine shaft. The plant has six 275,000-horsepower turbines - each capable of lighting 240,000 homes.

(4 -- ran in SAC edition only) This is part of the machinery that allows water to be brought into the Castaic Power Plant to generate electricity. The facility is one of California's few pump-storage plants.

(5 -- ran in SAC edition only) Superintendent Tom Lanski, a bearded, talkative man who has worked at the Castaic plant for 20 years, says the plant acts like a giant storage battery.

Hans Gutknecht/Staff Photographer

Map: CASTAIC POWER PLANT

SOURCE: Los Angeles Department of Water and Power 

Gregg Miller/Staff Artist