Biofuels in planes - coconuts?

Three million coconuts to get to Amsterdam? I'd rather take the train.

Over the last few months, four pilots in different corners of the world have held their breath, crossed their fingers (metaphorically) and, mid-air, flicked a switch to send a blend of kerosene jet-fuel and biofuel into their plane engines.

In these test flights, designed to see how jet engines run on biofuel/kerosene blends, the biofuels have been made from such diverse substances as jatropha (a tropical shrub), babassu nut oil, coconuts and even algae. If nothing else, it's great public relations. (Even if the test flights have used very small amounts of biofuel - a Virgin test flight had only one out of four engines powered by a measly 20 per cent biofuel.)

The aim of the tests has been to show that biofuels can safely power aircraft. And for the airline industry, the good news is that it seems to work, at least in small amounts - all four flights apparently went without a hitch. So does this usher in a bold new age of clean, green air travel? Well, probably not.

The aviation industry see biofuels as the holy grail - mainly because they might help insulate their profits from volatile oil prices, but also because 'green' fuels might be a way to avoid all the bad publicity they've been getting over the whole climate change thing. Meanwhile, the UK government are using the rather vague possibility of 'greener' planes as one of their 'get out of jail free' cards for going ahead with Heathrow expansion - despite themselves identifying that biofuels may be better suited to road transport or power generation (pdf). Of course, rhetoric about biofuels is one easy way to avoid talking about the serious environmental impact a third runway would have. (Interestingly, the Virgin test was probably timed to provide a bit of good spin for the Heathrow issue.)

Like most holy grails it sounds good - and may well prove quite elusive. The problem is that knowing planes can run on biofuels doesn't really get us much further towards sustainable aviation. Considering the environmental drawbacks of biofuel production, and looking at how much of the stuff you'd need to produce, it's clear there are some pretty serious problems.

The social and environmental downsides of biofuels are well documented, both by us and others. When biofuels are made from food crops, food prices rocket as food is turned into fuel. Last year, a leaked World Bank report said the steep food price rises of around 75 per cent seen over the year were mainly driven by biofuel production in US and Europe.

The industry answer was to develop biofuels made from non-food crops, like jatropha, which can grow on land that's not really suitable for food crops. But the obvious point is that what grows on poor land grows even better on agricultural land - so if there's high demand for biofuels, there will always be the same pressure on growing space.

More demand for growing space means more land clearing - whether to grow the biofuel crops, or to make space to grow the food crops they've displaced. And if tropical forests are being felled to make way for biofuel production, that's not doing the climate any favours - biofuels can be worse for the climate than the fossil fuels they replace.

Because of all this, the latest biofuel buzzword is algae - making fuel from algae grown in the oceans and (in theory) avoiding competing for growing space with food crops or ancient forests. But algae technology is only at the very early stages. What looked good with oil over $150 a barrel might be a bit less attractive now oil is relatively cheap again, and the airlines aren't so desperate for an alternative. With the global economy having a bit of a wobble, funding is falling away - we're not looking at any big amounts of fuel any time soon.

The recent test flights have been a highly successful PR exercise for the airlines. (Although occasionally the mask slips - check out a slightly mad contribution on the subject from Virgin's corporate affairs director.) But actually do the sums on how much fuel is needed and it begins to look even more style over substance. Even the small percentages of biofuel blends used will have required a lot of biological material to produce. Virgin's flight from London to Amsterdam used 22 tonnes of fuel but only 5 per cent of that was biofuel. Even producing that much required 150,000 coconuts. To power the whole flight would have taken three million coconuts - just to get to Amsterdam.

The global aviation industry uses about 240 million tonnes of kerosene a year - that's either a hell of a lot of coconuts, or roughly twice the area of France given over to growing biofuel crops. Maybe we need to think again?