INTERVIEW WITH PAUL KUENTZMANN (ONERA) : '30% BIOFUELS IN AIRCRAFT BY AROUND 2020'.

Paul Kuentzmann is Senior Scientific Adviser at Onera, the French aeronautics and space research centre. From 1996 to 2005, he was scientific director for fluids and energetics. As a specialist in aviation fuels, he comments here on research into alternative fuels.

Do synthetic fuels represent an attractive option?

There have been flight demonstrations with satisfactory results. The aircraft flies normally and there is no apparent difference between an aircraft fuelled with traditional jet fuel and one fuelled with synthetic fuel. There are even slight advantages because the synthetic fuels form less soot than traditional fuels, which is interesting for air quality in and around airports. They contain fewer aromatic chemical species than traditional jet fuel and aromatics are precursors of soot. Installations are being built today for the production of GTL [Ed.: gas to liquid, synthetic liquid fuel derived from natural gas]. The process - known as Fischer Tropsch' - has been mastered. It dates from the 1920s and was used during the Second World War in Germany to produce aviation fuels.

If these technologies have existed for years, why are they not being used more today?

There are two problems. First, there are not enough plants to provide the volumes required. At present, only Sasol [Ed.: Suid Afrikaanse Steenkool en Olie - South African Coal and Oil, a petrochemical company] has major industrial installations. However, Shell and Qatar Petroleum are in the process of building a large plant to produce GTL and others are considering working from coal. The second problem is that, if the whole chain is taken into account, CO2 emissions are high. More CO2 is emitted than with traditional oil refineries. So on the one hand, we stand to win in terms of energy independence, but on the other we lose in terms of climate change.

So does that make it a credible solution?

It is a solution that primarily interests the military. Many American military aircraft have already flown using these blends, and some civilian aircraft as well. Synthetic fuels can also be considered transitional fuels until more interesting options can be developed. The question is whether there will be investments in big plants to produce the quantities needed. Some oil companies, like Shell, are moving forward, but others are waiting.

The other possibility is biofuels

For the moment, though, we're still at the stage of scientific research rather than industrial production. The...