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Refuelling the future: Sustainable, drop-in aviation biofuel is a reality but challenges remain, says Boeing

Refuelling the future: Sustainable, drop-in aviation biofuel is a reality but challenges remain, says Boeing

Jim Kinder (left) and Jean-Philippe Belieres of the Boeing Commercial Airplanes Fuels and Thermals team examine algal-based fuel samples during routine lab testing in Seattle (photo: Boeing)

Tue 8 May 2012 – Back in 2005, the idea of using biofuels to power commercial and military jets seemed beyond the range of modern science. While suitable for cars and trucks, biofuels offered little hope they could meet the stringent requirements of commercial airplanes and high-performance jet engines. But in 2006, Boeing product development professionals became aware of research that challenged the notion that biofuels could not compete with traditional kerosene-based jet fuel in terms of energy content, technical performance, infrastructure requirements and cost. They reached out to others in the industry to determine whether biofuels could help meet the environmental challenges of commercial aviation. And their efforts paid off in a big way, reports Boeing’s Bill Seil.


“It was a dream five years ago, and now it’s a reality,” said Billy Glover, Vice President, Environment and Aviation Policy, Boeing Commercial Airplanes. Biofuels that can be used as a ‘drop-in’ replacement for kerosene are “not only feasible but highly desirable. The next step is to make it commercially viable.”


Although Boeing has no plans to produce aviation biofuels, it has taken a leading role in accelerating their development. It’s critically important for Boeing, its customers and the aerospace industry to reduce the environmental impact of jet aircraft, as well as to have another option for fuel supply, Glover said.


In 2006, Glover and Dave Daggett, a Technical Fellow with Commercial Airplanes, worked with the Federal Aviation Administration to hold an industry fact-finding meeting on aviation biofuels. This led to the creation of the Commercial Aviation Alternative Fuels Initiative (CAAFI), which has worked to advance the development of aviation biofuels from sustainable, or renewable, sources.


In early 2007, Glover formed a team that set the ambitious goal of conducting the first commercial airplane biofuel test flight within one year. That goal was accomplished in February 2008, when Boeing, Virgin Atlantic and General Electric joined forces to fly a Boeing 747-400 from London to Amsterdam with a 20/80 biofuel-to-jet-fuel blend in one of the four engines. The challenge then became how to develop the next generation of aviation biofuel that would move the industry beyond what was used to power the Virgin Atlantic flight.


“By the time we completed that flight, we were already on our way to planning three even more ambitious flights to be conducted over the next year,” Glover said. “They involved three different airline customers, three different engine manufacturers, three different regions of the world and several different biomass sources.”


Considerable progress has been made since the early test flights of 2008 and 2009. In August 2011, an Aeromexico Boeing 777-200ER completed the first intercontinental biofuel flight with revenue passengers as it flew from Mexico City to Madrid with more than 250 people on board. It used a 30% jatropha-plant-to-kerosene blend.


Later in the year, United Airlines operated the first commercial flight powered with biofuel derived from algae, and Alaska Airlines became the first US carrier to offer regularly scheduled passenger flights on airplanes powered by biofuels.


Although considerable progress has been made, there is still a long way to go, Glover said.


“We’ve set ourselves the goal of having 1% of all aviation fuel include some biofuel content by the year 2015,” he said. “We view that as the hardest 1%. After that, the learning curve improves and it becomes easier to get to 5%, 10% and so on.”



ASTM regulatory milestone


Ned Ferguson, Director, Environment, Government Operations, said one important regulatory milestone was the approval last year by ASTM International for the use of up to a 50% blend of hydroprocessed (treated with hydrogen), renewable jet fuels and conventional kerosene in jet aircraft. This decision by ASTM, a globally recognised technical standards organisation, was supported by the Federal Aviation Administration.


Both previously had approved the use of fuels produced with the Fischer-Tropsch process, which makes hydrocarbons by gasifying a diverse variety of materials such as biomass or coal.


The approval of these two processes – hydroprocessing and Fischer-Tropsch – meant for the first time that methods were available for the mass production of aviation biofuels made from plant and animal matter, and that aviation could fly using fuels from sources other than crude oil. Most recently, the use of hydroprocessing and other new approaches have significantly improved on Fischer-Tropsch by allowing biofuels to be produced using purely renewable sources at much reduced cost with lower carbon dioxide emissions.


But this is just the beginning, according to Glover. Boeing is working with partners to get approval for other biofuel processes.


“I’d say the key challenge that’s in front of us now is making the use of biofuels economical,” Ferguson said. “We need to reach the point where these fuels can stand on their own and compete with petroleum.” Also, the US Environmental Protection Agency has set ambitious environmental requirements for biofuels. To meet standards, advanced biofuels must achieve a 50% life-cycle reduction in greenhouse gas emissions over current fuels.


But help is coming from many directions.


In August 2011, the US Navy, the Department of Energy and the Department of Agriculture announced the agencies were committing $510 million to advance the production and use of aviation and marine biofuels in the United States. Both the US Air Force and Navy have set goals to have a substantial portion of their domestic fuel sources coming from biofuels by 2016, providing this can be done affordably.


On April 22 – Earth Day – in 2010, the Navy demonstrated its biofuel-powered Boeing F/A-18 Super Hornet, dubbed the ‘Green Hornet’. The following January, the Air Force certified the Boeing C-17 Globemaster III for unlimited use on hydroprocessed blended biofuels. The Air Force has also tested and certified biofuel as a 50% blend with regular jet fuel in the F-15E Strike Eagle, the A-10 Thunderbolt II and the F-22 Raptor. And a Boeing AH-64D Apache, flown by the Royal Netherlands Air Force, became the first rotorcraft in the world to fly using biofuels in mid-2010.



A company-wide effort


While by agreement Commercial Airplanes has taken the lead in Boeing’s biofuels development, it is a company-wide effort.


Tim Vinopal, Director, Environment, Health and Safety Engineering for Boeing Defense, Space & Security, said military customers are seeking to improve the environmental performance of their fleets. But this is not their only interest in biofuels.


They are looking for “diversified sources of fuel to supplement fossil fuels,” Vinopal said. “They see biofuels as a way to maintain secure sources of fuel and reduce cost volatility, while supporting their Commander in Chief’s environmental initiatives.”


Vinopal noted that while the same types of biofuels can be used in both commercial and military airplanes, military products are initially requiring additional testing. This is due, in part, to the wider range of operations performed by military products. There is, however, tremendous synergy and cooperation between the testing programmes for various military products and the civilian jet industry, he said.


Boeing’s focus is on the development of sustainable aviation biofuels that don’t compete with the planet’s food, water or land-use resources, said Darrin Morgan, Director, Sustainable Aviation Fuels, Commercial Airplanes.


Morgan said the Sustainable Aviation Fuel Users Group, of which Boeing is a founding member, clearly defines the conditions a biofuel must meet to be sustainable.


For example, the biomass materials used to produce the biofuel must be products such as algae or jatropha and camelina plants that are not part of the food supply. Biofuels must also, through their entire life-cycle, produce lower greenhouse gas emissions than conventional jet fuel does. This includes the byproducts of growing and processing the plants into fuel in addition to emissions from the airplane itself. For example, the production of any fertiliser for biofuel crops requires energy, which may involve the use of petroleum.


From a sustainability standpoint, biofuels have one big advantage over fossil fuels, said Morgan: Modern biofuels have a lower carbon footprint.


“Oil comes from plants that grew long ago when our atmosphere was much more greenhouse gas-intense,” Morgan said. “When we burn oil it releases carbon into the atmosphere that has been sequestered for hundreds of millions of years.”


Most of today’s biofuel development around the world aims to make use of plants that can be locally grown. In addition to the environmental benefits of biofuels, production can advance the economic development of countries or regions that have large areas of land and water not suited or developed for the large-scale production of food, but adequate for the production of non-edible biomass. At present, it appears most biofuels will be used to supplement fossil fuels within the regions where they are grown.


Bill Lyons, Director, Strategic R&D Partnerships, Boeing Research & Technology, said research programmes taking place around the world are exploring multiple processes and biomass sources for the production of sustainable aviation biofuels. However, the company is taking a ‘One Boeing’ approach to ensure that information is shared and there is a combined outcome that provides the best solutions for the aviation industry as a whole.


“One of the challenges right now is to get everybody in the value chain to feel like there’s enough certainty in their piece of the industry so they’re confident in making investment decisions,” Lyons said. Boeing has, and will continue to play, an important role in making that happen.



This article is reproduced with the kind permission of Boeing. A longer version appeared in the March 2012 edition of Boeing Frontiers magazine (boeingfrontiers@boeing.com).




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