Are biofuel flights good news for the environment?

Airlines are starting to test biofuels on commercial routes, but 'sustainable' alternatives to kerosene remain controversial

Thomson Airways ran a biofuel-powered flight to the Canary Islands in October 2011.

Are biofuel flights really a good thing for the environment? How can we ever produce enough biofuels to power all flights? And won't they just consume precious land that could be used to grow food instead?

Last week saw the first commercial flight part-powered by biofuels take off from a UK airport. The TUI Travel Boeing 757 flight from Birmingham to Lanzarote took off and landed without any reported hitches. No technical modifications were made to the plane with one of its two engines powered with a 50/50 blend of conventional Jet A1 fuel and a "Hydroprocessed Esters and Fatty Acids" fuel produced from used cooking oil. TUI Travel said the fuel was supplied by a Dutch firm called SkyNRG and that the fuel was "approved as sustainable by WWF and the Roundtable on Sustainable Biofuels".

Judging by the increasing number of airlines around the world announcing such flights, and the likely imminent inclusion by the EU of aviation within its emissions trading scheme, it would appear that biofuels are likely to play a very significant role in the future of aviation. Aviation - unlike its ground-based transport alternatives - is currently totally reliant on fuels with the energy density offered by a fossil fuel such as kerosene. So a plug-and-play biofuel substitute for kerosene seems to be the only viable alternative at present. After all, we can't electrify our planes or power them by nuclear fission (or not in a way that would be accepted by paying passengers) - and most aircraft operating or purchased today have a predicted lifespan of at least 40 years.

But just how "sustainable" are the biofuels used in aircraft? And will they only act to force up food prices? To rely solely on second-hand cooking oil seems complete folly. But the aviation industry says it is only using this source of biofuel for demonstration purposes. TUI Travel, for example, says it is looking at using biofuels made from the "purge family of plants as well as from camelina". Meanwhile, Virgin has just announced a "breakthrough" in biofuel production with a fuel produced from "reprocessed waste gases from industrial steel production". And other aviation fuel developers say they are exploring algae-based biofuels.

Or, perhaps, all this talk of biofuels is a convenient distraction: with aviation said to be the fastest-growing source of greenhouse gas emissions, should we instead be concentrating on reducing the number of aircraft we send into the sky? Or is aviation so crucial to us all that it deserves a special status of exemption, as it has long enjoyed when it comes to fuel duty and VAT?