SDG&E; Stages Slick Rehearsal for Disaster : Oil spill: Annual drill ensures that the utility’s 36-year history of pumping from off-shore tankers, marred by one minor spill, stays clean.

The oil spill recovery vessel moved slowly and steadily Wednesday morning, uncoiling 2,000 feet of inflatable boom into the ocean about three-quarters of a mile off the Carlsbad coast.

The boom bobbed, orange and ominous, as a 13-man, clean-up crew maneuvered it into a U-shape, threw absorbent pads into the water and deployed an oil skimmer with a tall crane.

From the looks of it, the only thing San Diego Gas & Electric’s mock oil spill lacked was an actual sheen on the water--to see this slick, you had to use your imagination.

It was all part of an annual drill required by the U.S. Coast Guard to ensure that the power company is prepared for an accident. And given their admirable track record, SDG&E; officials joked, they could probably use the practice. In 36 years of pumping oil from offshore tankers into the Encina Power Plant, SDG&E; officials claim they have spilled only 10 barrels of diesel oil, and none of that ever reached the shore.

Carl Johnston, a SDG&E; fueling supervisor, said the company currently averages about five tanker deliveries a year--down from about 30 deliveries a decade ago, before the plant began burning mostly natural gas.

For each of those deliveries, the utility has contracted with a Long Beach-based oil recovery company, American Work Boats, to be on hand when the tanker arrives. The company was involved in mopping up after the Huntington Beach oil spill and worked on the nation’s worst spill after the Exxon Valdez tanker ran aground in Alaska’s Prince William Sound.

The average delivery to the Encina plant, Johnston said, is 250,000 barrels or 10.5 million gallons of refined oil--almost as much as the Alaska spill. So, while Wednesday’s exercise was more pantomime than performance, he said the amount of oil at stake--and its potentially devastating effects on the coastline--made it worth the effort.

At 9:05 a.m., the Buccaneer, a 110-foot oil recovery vessel, faced into the wind and began unwinding its inflatable boom from a large spool at its stern. Twenty-two minutes later, the boom lay in a graceful arc on the water, surrounding an imaginary spill.

Then the Buccaneer handed the boom’s reins to a smaller boat, freeing itself to traverse the water inside the orange loop. A crane lowered a skimmer over the Buccaneer’s side to scoop up the nonexistent slick and pump it into storage tanks on deck.

That is how it is supposed to work, Lt. Cmdr. Pat Keane said.

“They put it (the boom) down pretty quick. They got the absorbent pads down and then collected them all again,” said the chief of the Coast Guard’s Marine Safety Office port operations department.

Ideally, Keane said, “we’d love to get everything out there and set up in an hour--that would be perfect. . . . They did pretty well.”