Alternative fuels move nearer to full commercial aviation use as an important specification hurdle is cleared
(photo: Continental Airlines)
Fri 26 Jun 2009 – A new aviation fuel specification, provisionally labelled DXXXX, has been passed by the ASTM International Aviation Fuels subcommittee that will enable the use of synthetic fuels in aviation. This new specification constructs a framework to facilitate the use of multiple alternative fuels (including both non-renewable and renewable blends), and targets complete interchangeability with conventional fuels produced to the standard aviation jet fuel specification D1655. The Air Transport Association of America (ATA) described the step, which is anticipated to receive full ASTM approval later this year, as a “watershed event”.
The DXXXX specification – which will be redesignated when finalized – is being structured, via annexes, to accommodate different classes of alternative fuels. The initial issue of the specification will enable use of fuels from the Fischer-Tropsch (FT) process up to a 50% blend with conventional Jet A aviation fuel. FT fuels can be generated from a variety of feedstocks, including biomass (biomass-to-liquid), natural gas-to-liquid and coal-to-liquid.
It is expected that the FT approval will be followed by approvals for blends of hydrotreated renewable jet (HRJ) fuels – biofuels derived from fats as well as oils from feedstocks such as jatropha, camelina and algae – and other alternatives as data from technical evaluations is obtained. An ASTM-required research report on HRJ fuels is expected by year-end. According to the Commercial Aviation Alternative Fuels Initiative (CAAFI), an FAA and industry group that advances the production and acceptance of alternative aviation fuels, a favourable evaluation of the report will support the incorporation of HRJ fuels into the new D-XXXX specification by the end of 2010, paving the way for the introduction of biofuel blends into commercial use.
The proposed specification describes the fuel properties and criteria necessary to control the manufacture and quality of these fuels for drop-in aviation use.
“The action of the ASTM subcommittee is a landmark step for all consumers of jet fuel,” said ATA President and CEO James May. “It signals the beginning of a new era for widespread production and use of cleaner, alternative fuels that not only will help the airline industry meet its environmental goals but also will provide airlines with more competitive options for purchasing jet fuel while simultaneously enhancing US energy security.”
The ATA’s Vice President of Environmental Affairs, Nancy Young, described the outcome as “extremely positive” and noted that “this is a giant step towards the adoption of the first of what promises to be several generic alternative jet fuel blends that will offer commercial aviation a sustainable new fuel dynamic. The airline industry is prepared to be an enthusiastic buyer.”
The approval was also welcomed by the Aerospace Industries Association (AIA), which represents leading US aerospace manufacturers and is a CAAFI member, who said it was a “significant step towards the broad production and use of cleaner aviation fuels that combat global warming and enable future aviation growth.”
Marion Blakey, AIA President and CEO, said: “It will send a strong signal to those developing alternative jet fuel technologies and production facilities that there is a clear path to market for cleaner fuels.”
