Authorisation of biofuels for use in commercial aviation is still expected to take place in the first quarter of 2011, despite the failure of an ASTM International subcommittee to give the anticipated green light in mid-December.
Richard Altman, executive director of the Commercial Aviation Alternative Fuels Initiative (CAAFI), had been hoping the ASTM subcommittee would authorise hydrotreated renewable jet (HRJ) fuel during a series of meetings held in December, but this did not happen.
However, he points out that the work is "99% done" and is confident the full ASTM committee will still be able to vote on whether to approve the fuels before the end of the first quarter, as originally planned. "It's not ideal, but we're okay with the outcome," says Altman.
ASTM approval is expected to kick-start the massive amounts of investment needed to scale-up production of aviation biofuels to commercially-viable levels.
"Until biofuels are certified, investment won't happen. No one is going to make a million gallons of fuel if they can't sell it," says James Kinder, chairman of the ASTM emerging fuels task force and technical fellow at Boeing Commercial Airplanes.
Predictions vary over the amount of biofuel that will eventually be used in aviation, as many questions remain unanswered. British Airways head of environment Jonathan Counsell says it will be a "slow ramp-up" but by 2050 "I fundamentally believe biofuels will play a significant role".
A number of airlines have already pledged to purchase alternative fuels as and when they become available. Germany's Lufthansa, for instance, aims to become the first airline to operate commercial passenger flights using an aircraft powered by a 50/50 biofuel blend derived from vegetable oil when it begins a six-month trial period in April.
Meanwhile, British Airways has agreed to buy all of the fuel produced by US bioenergy group Solena's proposed plant in east London. "The Solena project will supply 2% of BA's fuel demand," says Counsell. "Once it's successful, we'll build lots of these."
And in Latin America, Brazil's TAM has outlined plans to grow a crop of Jatropha curcas for use in biofuel tests, following the successful completion of a biofuel demonstration flight in November.
Further out on the horizon are biofuels derived from algae, which CAAFI's Altman describes as "our nirvana" and BA's Counsell calls "the great hope", and jet fuel derived from liquid hydrogen.