How many coconuts does a Boeing 747 need to fly from London to Amsterdam?
Last year amid much fanfare, a Virgin Atlantic 747-400 with one of its four engines fueled by a mix of 80 percent jet-A and 20 percent coconut and babassu oils flew the route in 40 minutes. Had all four engines been flying on biofuels alone, it would have required the oil from several million coconuts.

This was not the first flight of a biofuel-powered jet nor the highest concentration of biofuel mixed with jet-A. In 2007, a Czech L-29 with fuel warmers flew for 37 minutes to 17,000 feet with a 100-percent mixture of B100 biodiesel distilled from canola oil. Earlier this year, a Continental 737-800 with CFM56-7B engines flew for 90 minutes. Engine number-one flew on pure jet-A while engine number two was powered by a 50-50 mix of jet-A and a biofuel blend derived from algae and jatropha plants. And in January, a Japan Airlines 747-300 successfully flew with a biofuel blend largely of camelina.

Later this year, the U.S. Navy is to static test biofuels made from algae and camelina, an oilseed plant, in the GE414 engines of an F/A-18 Super Hornet. The Navy plans to test fly with biofuel next year and wants to test, select and certify an alternative fuel additive for its JP-5 fuel by 2013.

Honeywell and Pratt & Whitney Canada are also testing biological brews in their business jet engines. Honeywell is ground testing it on the TFE731-5 and Pratt & Whitney Canada on the PW615.

Early test results are all good– so far–with de minimus increases or decreases in engine performance, but a drop in greenhouse gas emissions of 60 to 80 percent. There is a growing body of science to support these results in the top three leading raw material additive contenders for jet biofuels–algae, camelina seeds and jatropha plants. A recent study at Michigan Technological University verified that jet fuel derived from camelina seeds lowers carbon emissions by 80 percent.

However, biofuels are unlikely to come to your local FBO anytime soon. There are significant technical challenges to flying with 100 percent biofuel. As a class, they are not as dense as jet-A, do not lubricate as well and do not contain the aromatic compounds necessary to penetrate seals and gaskets and promote swelling. So flying with anything other than at least a 50-50 jet-A/biofuel mix would require substantial modification of existing engines.

Then there is the small matter of price. Aircraft are exempted in the latest draft of the “cap-and-trade” carbon offset legislation making its way through Congress (the American Clean Energy and Security Act of 2009). However, increased cost to refiners under the bill is likely to raise the price of jet-A by 83 cents per gallon, or about 20 percent, according to the American Petroleum Institute. Bad as this is, running on biofuels or biofuel blends would cost substantially more. Producing a gallon of jet-grade biofuel costs four to 12 times as much as producing a gallon of straight jet-A.

Some of this disparity can be attributed to economies of scale, but the false assumption that costs would fall precipitously as production went up is seen by many as driving the current and widespread financial carnage in the automobile ethanol industry.

Last year, despite high oil prices and a record ethanol output of nine billion gallons–a 50-percent increase over 2007–the nation’s second-largest ethanol producer (VeraSun) filed for bankruptcy, as did numerous smaller producers. Without the current $9 billion in direct federal government annual subsidies and billions more in indirect subsidies, as well as loans, grants, tax credits, deferrals and exemptions from state and local governments to the domestic ethanol industry, it is likely the results would have been even worse.

In a 2006 report filed with the Securities and Exchange Commission, VeraSun acknowledged that the “U.S. ethanol industry is highly dependent upon myriad federal and state legislation and regulation and any changes in legislation or regulation could materially and adversely affect our results of operations and financial position.”

Ethanol is unsuitable for aircraft applications because of its lower energy value and easy ignition.

However, despite the biofuel math and some of ethanol’s unhappy history, the stampede into biofuels and aviation biofuels continues, with incentives provided by large government subsidies. The San Diego area has become a hotbed for biotech energy companies and is home to more than 200 of them, including several large ventures dedicated to algae fuel research.

The Department of Defense has paid nearly $50 million to two local companies–Science International and General Atomics (the same company that makes the Predator series of unmanned drones)–for algae research. According to Biofuels Digest, in 2008 $176 million in private venture capital flowed into algae biofuel projects. ExxonMobil has also made a $600 million bet on the technology.

Established OEMs are also taking notice. Earlier this month the Algae Biomass Summit convened in San Diego. Boeing and Airbus were major sponsors of the event and Honeywell’s Universal Oil Products unit was a major participant.

Algae is far from the only game in aviation biofuels. As mentioned earlier, two land crops, camelina (commonly known as “false flax”) and jatropha, a woody plant that grows in arid conditions, also are seen as promising contenders.

Currently, most biofuels are refined for ground vehicles and are soybean-based, and 80 percent of the 680 million gallons of U.S.-produced biodiesel was driven by exports to the European Union. But that came to a screeching halt in March when the EU imposed an anti-dumping ban, accusing U.S. firms of selling the fuel below cost. That, combined with a sharp spike in soybean prices, sent the nascent domestic biofuels industry into a sharp slide. In recent months the Nasdaq has threatened to delist several biofuels companies for not meeting minimum equity requirements.

Ground vehicles are likely the first place biofuels will appear at airports. Eight airlines serving Los Angeles International signed an agreement with Rentech to purchase up to 1.5 million gallons of RenDiesel refined from yard clippings to power their ground vehicles at the airport beginning in late 2012.

However, the standards development roadwork for aviation biofuels is continuing.
In August, the ASTM International Committee on Petroleum Products and Lubricants passed a synthetic fuel standard, D7566, “Aviation Turbine Fuel Containing Synthesized Hydrocarbons,” which will allow synthetic fuels derived from non-petroleum sources to be used in aviation.