Boeing has tested two such "vegetable-based biofuels" with this antifreezing property in the General Electric jet engines used on many of its 747 aircraft, Daggett says. Virgin Atlantic airline announced that early this year it will conduct the first flight test of a biodiesel–petroleum diesel blend in one of the four engines of a 747 aircraft; Air New Zealand is planning a similar test flight on a Rolls Royce engine in one of its 747s later in the year.
The first UOP-derived ecofining facility, capable of producing 100 million gallons of diesel fuel for ground vehicles, is now being built in Livorno, Italy; a second facility is set to be constructed in Sines, Portugal. "Going to biofuels doesn't mean we have to make compromises. We are already making fuels that look exactly like the real thing, or better," says Jennifer Holmgren, UOP's director of renewable energy chemicals. "The real limitation is going to be feedstock."
There is not enough oil from plants such as soy and canola to supply even a fraction of the 60 million–plus gallons of jet fuel burned every day by U.S. aircraft, nearly one quarter of global use, even if all such sources were converted to fuel (which would significantly impact food supplies.) And Boeing has had a hard time finding biofuel suppliers who can produce testable quantities of their product. "Immediately that weeds out a lot of companies when you ask for 1,000 gallons," Daggett says.
As a result, both private companies like UOP, government agencies like DARPA and commercial organizations such as CAAFI have begun to consider a broader array of sources, including the oil from the seeds of Brazil's babassu palm tree or the conversion of the woody or cellulosic parts of plants. Chemical engineer Charles Wyman of the University of California, Riverside, argues for biorefineries turning seed oil, the stalks and other detritus of crop plants, and even wood pulp waste into an assortment of alternative fuels.
"You are growing wood or grasses in a renewable way in some sort of energy plantation to produce biomass," he says. "Convert some of that to ethanol, and the fraction you can't convert, use Fischer-Tropsch to make diesel fuel that could be tailored towards jet fuel."
Or algae could be grown. The tiny plant can produce "60 percent of its weight as oil under stress," according to Wyman. Closed vats might produce pure strains of such high-oil species for feeding into large ponds to grow sufficient supplies, says systems engineer Ron Pate at Sandia National Laboratories in New Mexico, who has been analyzing the fuel potential of microscopic plants.
Such vast algae farms might also subsist on so-called "impaired" water, either salty ocean or polluted waters, Pate says. "Water coming out of sewage treatment plants has nutrients—nitrates, which encourage algae to grow," Boeing's Daggett notes. "You can harvest the algae and extract the oil, then release the water in a cleaner state than what it would have been leaving the sewage plant."
But biorefineries would cost hundreds of millions of dollars and require significant upgrades in existing processes, whereas such algae schemes have yet to be tried. The U.S. Department of Energy (DOE) has provided the money for a few pilot biorefineries and DARPA has provided funding for initial efforts to begin exploring algae's feasibility, but it will be years before any such fuel is widely available. "Ten to 20 years is a reasonable time frame," Daggett says.