Wed 13 Feb 2008 - At a media briefing in London yesterday, Bill Glover, Boeing’s Managing Director, Environmental Strategy, said that second generation biofuels could be used in regular commercial aviation services within five to seven years and, in time, reduce aviation’s carbon footprint by as much as 50%.
“It will take a while to get there but we’ve started on that journey and the results so far are very good,” he told journalists.
Second generation biofuels avoid the use of ethanol, which is unsuitable for aviation use, and the requirements of using large quantities of water and land, which has led to large-scale deforestation.
One of the problems with biofuel blends that has had to be overcome is that they freeze at high altitudes but Glover confirms tests have taken place where freezing points lower than petroleum have been achieved. There are other challenges in ensuring biofuels reach Jet-A fuel performance levels, such as meeting high temperature thermal stability, energy density, storage stability and elastomeric compatibility. The biofuel blends also have to be what Glover calls ‘drop-in’ solutions, whereby from a user or airline standpoint they are like any other fuel and can be used for refuelling any aircraft or engine type.
However, results so far have proved positive. “We are thrilled to have got so far so quickly – we really didn’t expect it,” says Glover.
A range of different types of biomass have been undergoing testing including algae, jotropha plants, halophytes and the nuts from babassu trees, but Glover says that although in terms of CO2 absorption and performance they are all similar, algae feedstocks have the greatest potential due to their superior yields.
Glover confirms that the two flights planned in conjunction with Virgin Atlantic and Air New Zealand, the former later this month and the other later in the year, will test different types of biofuels. The Virgin flight, a B747 flying from London to Amsterdam, will entail filling one of the four engines with a blended mix consisting of 80% ordinary Jet-A fuel and 20% biomass-to-liquid (BTL) fuel. The other three engines will carry normal Jet-A fuel.
Boeing says that the Virgin flight will mainly focus on the technical feasibility of BTL whereas the Air New Zealand test will seek to identify sustainable feedstocks.
Once tests have proved successful and biofuels are ready for commercial service, which Glover believes could within a five to seven year timeframe, the percentage of BTL content would initially start at only around 10% or even lower, mainly, says Glover, because of growing capacity constraints together with the need to build confidence across the airline industry first.
With regard to synthetic fuels produced from coal-to-liquid and gas-to-liquid processes, Glover acknowledges they have clean burn characteristics and their low sulphur content contributes to a better local air quality. But, he says, their carbon footprint is much higher than biomass-to-liquid. “BTL is a whole different ball-game,” he argues. “It has the same technical performance but with a much smaller footprint. BTL is the long term future and will bring the biggest benefit to the industry, so that’s where we are focusing our efforts.”
Glover confirms that Boeing is keen to share its knowledge and research on biofuels with all parties within the aerospace sector, including its rival Airbus. “This has to be something that works for the whole industry. We need everybody’s thoughts and engagement on this. All the parties to the two test flights have agreed to share the data with others in the industry.”
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