Biofuels for aviation, the next challenge
Quicknote aviation biofuels
Rudimentary map used to show how much land is needed to produce enough bioenergy to fuel all U.S. airtraffic - map used during heated 'Peak Oil' debate in 2004.
A few years ago, one of our members was involved in a roundtable on oil depletion - now commonly known as 'Peak Oil' - and he focused on the potential of biofuels. A question and a critique that kept coming up was the notion that with Peak Oil, the aviation industry would collapse first, since its fuel costs are the single most determining factor for its profits. Hydrogen would not save the industry because the gas requires entirely new and bulky airplanes; batteries are obviously out of the question as well; synthetic fuels are too expensive. "But how about bio-jetfuel?", our member asked. The critics laughed, brushed the idea off the table and went on to the next point on the agenda - aviation was doomed, no question about it.
Since then, a lot has changed, and biofuels for aviation are being taken seriously. First there was the Brazilian company Embraer that manufactured an airplane powered entirely by ethanol. Then visionary venture capitalist Richard Branson shocked the world by announcing that he is investing in aviation biofuels, predicting that they would supply 100% of his Virgin fleet of airplanes in the coming two decades (Recently he has broadened his idea and bets all out on Virgin Biofuels - for personal transport, trains and aviation). Later, Boeing produced an interesting report on renewable green aviation fuels - focussing on biojetfuel from first generation crops [see resources below]. And more recently the U.S. Defense Advanced Research Projects Agency (DARPA) released a solicitation calling under its Biofuel Program for the exploration of energy alternatives and fuel efficiency efforts in a bid to reduce the military’s reliance on traditional fossil fuels for aircraft. DARPA is looking for processes that will efficiently produce alternative non-petroleum based military jet fuel from agriculture or aquaculture crops.
Flying on biofuels is a serious challenge, though. Current commercial biofuel production processes do not yield alternative fuels that meet the higher energy density and wide operating temperature range necessary for civilian and military aviation uses. What is needed is the development of an affordable alternative production process that will achieve a 60 percent or greater conversion efficiency, by energy content, of crop oil to aviation fuel (JP-8) and elucidate a path to 90 percent conversions in order to stay competitive.
Ideally, such a production process uses limited sources of external energy, is adaptable to a range or blend of feedstock crop oils, and produces process by-products that have ancillary manufacturing or industrial value. Current first-generation biodiesel fuels are 25 percent lower in energy density than JP-8 and exhibit unacceptable cold- flow features at the lower extreme of the required JP-8 operating temperature range (minus 28 degrees C, -50 degrees F).
It is anticipated that the key technology developments needed to obtain these goals will result from a cross-disciplinary approach spanning the fields of process chemistry and engineering, materials engineering, biotechnology, and propulsion system engineering.
But at least, bio-jet fuel is being taken seriously. The laughs are over.
Resources:
ethanol :: biodiesel :: biobutanol :: biomass :: bioenergy :: biofuels :: energy :: sustainability :: Africa ::
Rudimentary map used to show how much land is needed to produce enough bioenergy to fuel all U.S. airtraffic - map used during heated 'Peak Oil' debate in 2004.
A few years ago, one of our members was involved in a roundtable on oil depletion - now commonly known as 'Peak Oil' - and he focused on the potential of biofuels. A question and a critique that kept coming up was the notion that with Peak Oil, the aviation industry would collapse first, since its fuel costs are the single most determining factor for its profits. Hydrogen would not save the industry because the gas requires entirely new and bulky airplanes; batteries are obviously out of the question as well; synthetic fuels are too expensive. "But how about bio-jetfuel?", our member asked. The critics laughed, brushed the idea off the table and went on to the next point on the agenda - aviation was doomed, no question about it.
Since then, a lot has changed, and biofuels for aviation are being taken seriously. First there was the Brazilian company Embraer that manufactured an airplane powered entirely by ethanol. Then visionary venture capitalist Richard Branson shocked the world by announcing that he is investing in aviation biofuels, predicting that they would supply 100% of his Virgin fleet of airplanes in the coming two decades (Recently he has broadened his idea and bets all out on Virgin Biofuels - for personal transport, trains and aviation). Later, Boeing produced an interesting report on renewable green aviation fuels - focussing on biojetfuel from first generation crops [see resources below]. And more recently the U.S. Defense Advanced Research Projects Agency (DARPA) released a solicitation calling under its Biofuel Program for the exploration of energy alternatives and fuel efficiency efforts in a bid to reduce the military’s reliance on traditional fossil fuels for aircraft. DARPA is looking for processes that will efficiently produce alternative non-petroleum based military jet fuel from agriculture or aquaculture crops.
Flying on biofuels is a serious challenge, though. Current commercial biofuel production processes do not yield alternative fuels that meet the higher energy density and wide operating temperature range necessary for civilian and military aviation uses. What is needed is the development of an affordable alternative production process that will achieve a 60 percent or greater conversion efficiency, by energy content, of crop oil to aviation fuel (JP-8) and elucidate a path to 90 percent conversions in order to stay competitive.
Ideally, such a production process uses limited sources of external energy, is adaptable to a range or blend of feedstock crop oils, and produces process by-products that have ancillary manufacturing or industrial value. Current first-generation biodiesel fuels are 25 percent lower in energy density than JP-8 and exhibit unacceptable cold- flow features at the lower extreme of the required JP-8 operating temperature range (minus 28 degrees C, -50 degrees F).
It is anticipated that the key technology developments needed to obtain these goals will result from a cross-disciplinary approach spanning the fields of process chemistry and engineering, materials engineering, biotechnology, and propulsion system engineering.
But at least, bio-jet fuel is being taken seriously. The laughs are over.
Resources:
- Dagget, Dave, Alternate Fuelled Aircraft, presented to Boeing’s Transportation Research Board, 23 january 2006 [*.pdf].
- The Potential for Renewable Energy Sources in Aviation [*.pdf]. Looks at the feasibility of nuclear aircraft (not safe), methanol and ethanol (too low energy density), bio-methane (low volumes and limited available quantity). Retained options: liquefied H2, synthetic kerosene (including Biomass-to-Liquids) and biokerosene (from oil crops).
- Worldchanging: Fly Green.
ethanol :: biodiesel :: biobutanol :: biomass :: bioenergy :: biofuels :: energy :: sustainability :: Africa ::
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