Washington state, already a leader in aviation biofuels research, took a step ahead Tuesday with the first flight of a jet partly powered by fuel derived from waste cooking oil and chicken fat.
While the kitchen origins of "green diesel" may seem mundane, 800 million gallons of such biowaste waste are converted into fuel annually. That means chip fat could be a significant source of aviation fuel in the future.
"Green diesel offers a tremendous opportunity to make sustainable aviation biofuel more available and more affordable for our customers," said Julie Felgar, managing director of Environmental Strategy and Integration, Boeing Commercial Airplanes, in a statement.
The new Boeing research complements work already being done around the state.
In 2013 the FAA announced creation of the Center of Excellence in Alternative Jet Fuels and Environment, based at Washington State University in Richland, and including the University of Washington among its 16 university partners.
In 2010 Boeing, airport operators, environmental groups and WSU formed Sustainable Aviation Fuels Northwest, a collaboration aimed at developing aviation fuels in Washington.
The "green diesel" is a different fuel from the biofuels, more like kerosene, that already have been tested by Boeing as well as by carriers including Alaska Airlines and Virgin Atlantic.
Green diesel is also chemically different and more complex than "biodiesel," a different derivative of waste cooking oil that people often use to fuel automobiles.
The Tuesday flight was by Boeing's ecoDemonstrator, a 787 Dreamliner that Boeing has dedicated to helping develop alternate fuels. The first plane flew with a 15 percent mix of green diesel in the left engine.
A second flight on Wednesday was powered by 15 percent green diesel in both engines.
A Boeing test pilot said the plane flew normally with the unusual fuel mix.
"The airplane performed as designed with the green diesel blend, just as it does with conventional jet fuel," said Capt. Mike Carriker, chief pilot for product development, in a statement. "This is exactly what we want to see in flight tests with a new type of fuel."
Boeing is trying to meet a goal of filling 1 percent of the world's demand for jet fuel with all of these green fuel projects by 2016. Since the combined consumption of jet fuel is about 60 billion gallons annually, meeting the goal would require 600 million gallons of that to be shifted to biofuels.
"If we can get green diesel approved, suddenly there would be a very large supply of fuel that is more affordable and valuable to our customers around the world," said Jessica Kowal, a spokeswoman for Boeing Commercial Airplanes' environmental programs.
Jet makers and airlines are serious about developing aviation biofuels, partly because regulators are stiffening standards for burning fossil fuels at altitude. In addition other potential sources of aircraft power, such as electric motors or fuel cells, so far haven't proven viable for commercial flights.
A Boeing team of half a dozen people in the Seattle area, and other Boeing people around the country, also are working on other projects to develop other types of biofuels for jets, Kowal said.
For instance, researchers are trying to produce aviation biofuel from a type of tobacco in South Africa, and from a plant called a halophyte, which can grow in salt water, in the United Arab Emirates.