Just a few years ago, the idea of replacing kerosene-based jet fuel with renewable fuel from plants seemed out of the question. The cost of producing such alternative fuels dwarfed that of traditional jet A-grade fuel, and moving a severely carbon-intensive industry toward cleaner fuels would only happen if the economics worked out.
A 2008 spike in oil prices and a global economic slowdown later, and suddenly bio-jet fuel isn't just back on the table, it might be in your airplane's engines in the next four or five years.
"Generally speaking, three years ago I think many people felt that it was something on paper and it was a bit of a pipe dream," said Steve Lott, the head of corporate communications for the airline industry group International Air Transport Association, or IATA. "The tests we've seen in the past two years or so have definitely moved the ball forward and accelerated the process forward toward certification."
The tests Lott mentioned are a series of flights by various airlines around the world demonstrating the capability of so-called "drop-in" biofuels. These fuels, derived from second-generation biomass sources like algae and the jatropha plant, can power a jet engine with no modification to the engine or plane, saving the industry from the economic impossibility of upgrading the worldwide airplane fleet.
Continental Airlines, for example, has already flown a demonstration flight using a 50-50 blend of kerosene and algae-based fuel in one engine of a Boeing 737, and Lott said there was even some indication that of the plane's two engines the biofuel-powered one performed slightly better than the kerosene engine.
Bullish on Algae
Algae — yes, the green stuff you see on ponds — has emerged as the most promising biomass source that could eventually be scaled up to commercial production levels. It can grow in brackish water and in areas that don't compete with food crops, and it has among the best energy-per-unit-area of growth of any biomass feedstock.
Although no large-scale production of algae-derived jet fuel has begun, there are indications that this will soon change. The U.S. Defense Advanced Research Project Agency, or DARPA, has an algae-to-jet fuel project that will begin testing this year, and it hopes to begin mass production by 2013. The agency hopes to demonstrate that production of algae triglyceride — which can then be converted into jet fuel — can come down in cost toward $1 per gallon, making it commercially viable. Only a few years ago, the cost was upwards of $100 per gallon.
Several companies in the U.S. are also attempting to move this field forward, including Solazyme and Sapphire Energy, two California-based companies that shared in $100 million in DOE grants announced in December for innovators working on renewable jet fuel. Solazyme said it is delivering 1,500 gallons of algae-derived jet fuel to the U.S. Navy, which plans to test the fuel this year.
Jim Proulx, a spokesperson for Boeing Commercial Airplanes, said his company is involved in several biofuel-related projects as well, although for the moment they are largely aimed at testing the feasibility of new types of fuels than actually pushing for a scale-up of commercial production.
"What we hope to see is something in the area of 10 percent [biofuel] use by 2015," he said. "It doesn't sound like much, but it is much. It is a couple billion gallons."
Algae may show the most promise for jet fuel production, but British Airways has taken a different approach. The company recently announced the opening of a plant that will convert about 500,000 tons of organic waste into 16 million gallons of jet fuel each year. The fuel will be put into use by 2014.
The waste-to-fuel plant will use a process known as Fischer-Tropsch to produce jet fuel. According to an industry-Federal Aviation Administration partnership called CAAFI — Commercial Aviation Alternative Fuels Initiative — plants that use that method rather than algae- or jatropha-based fuels will most likely have much higher capital costs. Fluctuating costs of algae and jatropha feedstocks, though, will play a big role in determining the feasibility of commercial production as well. As CAAFI concludes, "a sustainable business model that improves yields and encourages the growth of energy crops is required to ensure competitive costs."
Lott agreed that commercial-scale production will be a major obstacle to break through. Certification of some new fuels by various fuel standards groups is expected by early 2011, "and then after that, it's a matter of working with the production companies and suppliers and distribution."
"To ramp up production of this, it takes investment," he said. "In fact, we think really to do a global production and distribution network would require an investment of about $100 billion in production and distribution facilities. That's not a small drop in the bucket, it will require a huge investment."
Lott's group, the IATA, has stated a goal of at least 10 percent of jet fuel coming from renewable sources by 2017. Making that sort of progress would help take a huge bite out of global warming mitigation strategies: According to the Intergovernmental Panel of Climate Change, transportation in general accounted for about 23 percent of energy-related greenhouse gas emissions in 2004, and aviation used up about 11 percent of all transport energy. Estimates put air travel's contribution to global warming at about 5 percent, and worst-case scenarios show it could climb to as much as 15 percent in coming decades.
"We have answered the questions and technically, it is feasible, it can be done with these drop-in fuels," Lott said. "So it is not a question of 'if,' but a question of 'when.'"