VANCOUVER, Wash. — Its first nickname was "R2D2" after the "Star Wars" robot, but now they just call it "the dog" when it's time to drain the grease at Burgerville USA.

"The dog" is a small, stainless steel tank and pump combination on wheels that the Northwest restaurant chain has pioneered to channel used cooking oil to a biodiesel producer.

"It's the wave of the future," said Chris Wurtz, a Burgerville manager who demonstrated "the dog" at a new restaurant at the junction of Interstate 5 and Interstate 205 in Vancouver.

With the price of crude oil soaring, the restaurant industry could make a serious contribution to the fuel supply if most of its waste cooking oil can be recycled as biodiesel, according to industry and renewable fuel experts.

"It really does hold long-term benefits, not only for the restaurant industry, but for the environment on a national basis," said Hudson Riehle, senior vice president of research for the National Restaurant Association.

At the Burgerville restaurant, Wurtz towed "the dog" to the deep fryer, opened a steel cabinet door, turned a valve and started the oil flowing into the low-slung tank. When he had a big sample, he towed the pump to the back of the restaurant to transfer the old oil into a stainless steel holding tank.

The tank is fitted with a hose coupling that feeds through the back wall, where a truck from MRP Services, a plumbing and drain service company, can drive up, connect another hose, and drain the tank.

MRP, in turn, takes the oil to SeQuential Biofuels in Portland, where it is converted to biodiesel.

The arrangement saves Burgerville the cost of hauling away the grease, but it is expected to eventually bring in additional revenue as biodiesel producers develop a competitive market.

Used vegetable oil has been either waste or the stuff that restaurants had to pay to haul off.

Rising fuel prices, however, are pushing a switch to converting the used cooking oil into renewable biodiesel fuel as a routine part of the restaurant business.

"For us it's a straightforward proposition," said Jeff Harvey, chief operating officer of The Holland Inc., parent company of the chain of 39 Burgerville restaurants.

Burgerville restaurants now produce about 7,500 gallons of oil a month that can be turned into 6,400 gallons of biodiesel, company officials said.

Carlo Luri, biofuels manager for Bently Agrowdynamics in Minden, Nev., said that each American uses about 10 gallons of cooking oil a year. He said recapturing just half that amount of oil could trim conventional diesel fuel consumption by 1 percent to 2 percent nationally. Diesel fuel accounts for about 24 percent of oil refinery production nationally, according to the American Petroleum Institute.

Kelly King, vice president of Pacific Biodiesel Inc. in Hawai'i, said the company founded 10 years ago by her husband, Robert King, now converts most of the waste cooking oil collected around the state.

The couple began on Maui, where Robert King had the contract to maintain generators at the central landfill. He teamed up with University of Idaho researcher Daryl Reece to recycle discarded cooking oil into biodiesel to reduce the impact on the environment.

Kelly King noted that Hawai'i has already reached the goal of providing 2 percent of the total diesel consumption that Luri said could be reached nationally. Now the challenge is to find more renewable fuel sources.

"We're already there with used cooking oil," King said. "We need to come up with another oil seed crop to seriously displace diesel fuel."