Recent A-10 Test Was Just Latest Step In The Process
While the world searches for more efficient ways to fuel
automobiles and create usable energy, Air Force scientists are
looking for cleaner, more efficient ways to fuel the military's
aircraft. On March 25, an A-10 Thunderbolt II flew solely on a
blend of biomass-derived fuel and conventional JP-8 jet fuel - the
first flight of its kind.
Air Force Materiel Command fuels experts Jeff Braun, director of
the Air Force's alternative fuels certification office; Tim
Edwards, a senior chemical engineer with the Air Force Research
Laboratory's propulsion directorate; and Betty Rodriguez, chief
engineer for the alternative fuels certification office, direct the
research and certification of synthetic and biomass-derived
alternative aviation fuels from Wright-Patterson Air Force Base,
Ohio, and they participated in a "DoD Live" bloggers roundtable and
offered their perspectives on the history-making demonstration
flight.
The A-10 was powered by a blend of conventional JP-8 and a
biomass fuel derived from camelina, a nonfood rotation crop similar
to soybean and mustard. The alternative fuels certification office
is preparing to test fuels made primarily from plant oils and
animal fats. They are part of a family of fuels Braun said are
called "hydro-treatable renewable jet," or HRJ, fuels. He and his
colleagues hope to create biomass fuels that the Air Force will
certify for use across its spectrum of aircraft and support
vehicles.
The A-10 flight is the latest phase of a long research and
development process evaluating candidate biofuels from various
industry sources. Part of that process, Edwards said, is testing
different kinds of biomass materials and biomass processing
methods. "This is the first step of many we're going to follow
through," Rodriguez said. "We're going to continue expanding the
envelope, basically testing engines and testing aircraft."
To a certain extent, researchers can tailor the new biofuels by
specifying desirable chemical properties which enable clean
burning, for example. Braun underscored the Air Force is "feedstock
agnostic," noting that what the fuel was made from isn't important
so long as it has the desired performance and safety
specifications. "The way we look at it is to figure out what fuels
make the most sense from an aviation industry perspective -- which
ones have the potential to make the most fuel the most affordably
with the least environmental impact," Edwards said.
File Photo
He added that the Air Force Research Laboratory has invested a
lot of money in environmental research covering lifecycle
greenhouse gas footprints and other factors in developing materials
for bio-fuels. "We're just trying to figure out which kinds of
processes for making jet fuel for aviation seem to be the winners,
and look into those for further development," Edwards said.
A major benefit HRJ fuels offer the Air Force is that they can
be produced within existing refineries - new facilities don't
necessarily need to be built. But some new plants are being built
solely to produce biomass fuels such as HRJ or "green" diesel,
Edwards said.
One such refinery is being built by Tyson Foods and will use
animal fats from its food production factories to create biomass
fuels. Another company, called AltAir Fuels, is building an HRJ
plant near an existing refinery in Washington state, Edwards said.
"It turns out the primary cost comes from feed stock; the
processing isn't all that expensive," Edwards said. "In places
where you can get affordable feed stock, at least the industry
seems to think it's cost-effective, because they're getting capital
to start building plants."
The Air Force is the Defense Department's largest consumer of
jet fuel, but burns only the equivalent of a mid-sized airline.
It's closely cooperating with industry as part of a consortium of
commercial airlines and engine manufacturers called the Commercial
Aviation Alternative Fuels Initiative. The expectation is that once
biofuels are certified for use, production economies of scale will
make them affordable, on par with petroleum-based jet fuel.
Biomass fuels also can be made from algae and other plant oils.
Both options are being vigorously pursued by the aviation industry
and the Air Force as well, Edwards said. "Where we can get our
hands on algae oils, we've proven that those fuels are pretty much
the same as the camelina oil we flew on last week," Edwards said.
"Looking ahead to when algae hits it big - people are putting
hundreds of millions of dollars into it - we're helping to enable
that algae feedstock for aviation applications."
Reducing demand and increasing supply are two of the legs of the
Air Force's energy strategy, Edwards said, with a focus on creating
and building more effective, cleaner engines. Rodriguez added that
the advancement of biofuels and creating effective, efficient
blended fuels that can be dropped in without any modifications to
aircraft or systems are a big part of that.
Edwards said even as the Air Force prepares to begin
certification testing of HRJ fuels, scientists at the Air Force
Research Laboratory are exploring the next generation of new fuels,
made from cellulosic biomass sources or derived from advanced
fermentation processes that produce hydrocarbons. These aren't
nearly ready for certification, as they require further
development, Rodriguez said, but they do show promise.
"We're at the cutting edge of alternative fuels," Rodriguez
said. "Everybody's pulling together to make this possibility a
reality, to create a family of fuels we can burn safely and won't
impact the performance of our aircraft and ground support
equipment."