“We are pleased with these positive results. The flight went smoothly and the data collected enables us to better understand the impact of biofuel on the environment,” said John R McDougall, president of the NRC, which partnered with a number of firms – including biofuel suppliers - for the trial.
The NRC test is the latest in a series of demonstration flights aimed at proving the worth of biofuels. In 2008, Virgin Atlantic was the first to fly a plane on a blend of biofuel and regular jet fuel. Since then, the number of trials has increased year on year, withat least 15 airlines and several aircraft manufacturers performing flight tests with various blends containing up to 50% biofuel. And, in 2011, KLM became the first airline to test it in regular commercial flights between Amsterdam and Paris.
All of these tests – including trans-Atlantic flights - have shown that biofuel works well, improves efficiency and, crucially, can be “dropped in” to existing fuel infrastructure at airports.
With so many apparent advantages, you might expect that every airline is beginning to draw up a plan to use these fuels. But you would be wrong.
Biofuels are not without problems, leading the chief scientist of environmental group Greenpeace to label the first flight by Virgin as "high-altitude greenwash".
One of his main criticisms is that in some cases biofuels can lead to deforestation and a large increase in greenhouse gas emissions. It is a view backed up by a recent report from MIT, which cautioned that the entire life cycle of a fuel has to be assessed before it can be called ‘green’.
The 2011 analysis of 14 fuel sources, including conventional petroleum-based jet fuel, showed that emissions from burning biofuels varied hugely depending on the type of land used to grow the fuel-crops. For example, biofuels made with palm oil from a plantation made by clearing rainforest emitted 55 times more carbon dioxide (over its life cycle) than oil from a previously cleared area. The comparison with conventional fuels can look very different too. Crops grown in an unsustainable manner can actually create fuels that emit 10 times more CO2 than fossil-fuel based fuel.
“The situation is more complex than just looking to biofuels,” says Prof Barrett. “There are many types of biofuel, there are many different kinds of biomass which can be used to create biofuel, and there are many different ways of taking that biomass and converting it, and all of those things have different properties in terms of how much they cost and how efficient they are. We need to get more sophisticated about determining which ones make environmental sense.”
Other big challenges for biofuels include whether land used for growing the necessary crops is taking land away from growing food, and also just the sheer size of the land area that would be needed to cultivate enough biomass to feed the growing aviation industry.
As a result, scientists increasingly advocate the use of crops that grow in areas that would not normally support agriculture – such as salicornia, a salt loving plant – or the use of algae, which could potentially be grown in massive vertical vats or ponds. However, there is still a long way to go before these crops are grown on anything like the scale needed to support aviation.
But people like Boeing’s Dr Tracey believe it will happen.
“We are convinced that sustainable biofuels can provide a way to reduce the CO2 by between 60 and 80% on an airplane,” he told me. “We really do believe that by 2030, 30% of all airplane fuel could be provided by sustainable biofuels.”
And if you’re still concerned about flying in a plane powered by plants, his message is: don’t be. Although they are produced from a variety of sources, any fuel that finds its way into a plane is tightly controlled and regulated.
“There are 12 different parameters that you have to measure with exact precision to get certified to be a jet fuel,” he says. “We’ve flown on commercial flights, we’ve flown F18s over the speed of sound, C17s, Apache helicopters, you name it, it’s been flown. So this is not a technology question on whether these fuels will work or be safe. This is only a question of scale-up of production.”