DALLAS — Outside a North Dallas restaurant, a pulsing hose is connected to a small tank truck. The viscous fat moving through the hose is "yellow grease" — used cooking oil — produced by frying equipment.
The material has always been worth something, but it's value is going up.
"There's been a popularity around renewable energy, and the value of the oil has increased dramatically," said Mike Spahn of Liquid Environmental Solutions. His company pays restaurants for its used oil in 11 states.
LES collects oil, which is now traded as a commodity, purifies it, and resells it.
In Seattle, Alaska Airlines has used refined cooking oil as jet fuel. Last fall it announced it would try a product made by Dynamic Fuels, which has a plant in Louisiana, on 75 flights.
Dynamic uses cooking oil as a raw material in a purpose-built facility which can refine both animal fats and cooking oil into aircraft-ready fuel.
Dynamic's Robert Ames holds up a vial of the brown liquid before it's processed, "We take this basically from throughout the southern part of the United States around our plant," said Dynamic's Robert Ames. "We process it into clear, water-white jet fuel."
Making jet fuel from recycled oils is more complicated than producing bio-diesel. Jet fuel has to remain liquid at the very low temperatures of high altitude flight, while bio-diesel does not.
Currently, there is not a big enough used oil stream to produce the volume of jet fuel airlines require as a reliable fuel source. But Liquid Environmental, by developing a reliable collecting process, is one of several companies moving toward legitimizing the collection process.
"We provide a professional driver, uniformed with clean equipment," Spahn said. "We provide value to the customer by paying them a rebate for the oil. We process it. We sell it into renewable energy."
Liquid Environmental, headquartered in San Diego, now uses or owns 17 oil processing plants across the country. With airlines as a potential eventual customer, business is looking up.