29/07/2011 11:53 BST | Updated 27/09/2011 10:12 BST

Biofuels Fail To Take Flight

Carbon-emission campaigners are rarely given such a gift: the UK's first commercial flight powered by sustainable biofuels, criticised by some for being anything but, has been cancelled at the last minute due to 'delivery issues'.

Flight TOM7424, which was expected to leave from Birmingham for Palma on Thursday, was grounded due to "a delay beyond our control during the transportation of the sustainable biofuel," operator Thomson said in a statement.

The cancellation is an apt metaphor, environmental campaigners said, for a technology which is unlikely to deliver truly 'green' flights for some years to come, if ever.

So how green are biofuels in aviation? And what new technology is on the horizon that might prove to be (excuse the pun) more uplifting?

In a press release before the cancellation, Thomas said that the flight would be fuelled by a so-called sustainable mix of waste cooking oil and other biofuels.

"The environmental and social credentials of sustainable aviation biofuel, when done correctly, are undeniable," Thomson had said in a statement. "The purpose of these operations is to demonstrate to the investment community that there is a market for sustainable aviation biofuel."

As environmental groups have highlighted, however, and as Thomson itself admitted in a statement, that's only half true. The flight was actually going to operate on a 50-50 mix of waste cooking oil-derived biofuel and normal jet fuel, meaning that the potential 'benefits' of the flight were immediately cut in half.

Moreover, Friends of the Earth have pointed out that since the average person produces around one litre of waste cooking oil per year and the 3,000km flight to Palma uses around 100 litres of fuel per passenger, it would have taken each person on the flight 100 years to collect enough for one journey to the sunny Spanish island.

"You have to be realistic about the prospect of scaling this up because you can do a few test flights on recycled cooking oil but you can't run the whole aviation industry on that," said Kenneth Richter, a biofuels campaigner for Friends of the Earth.

The point is that waste cooking oil can only ever be a temporary solution. Ultimately current generation biofuels, if used more widely, will be produced using the same crops as motor biofuels. That introduces a host of problems and is arguably worse for the planet than fossil fuels.

"You need a massive amount of land to produce this fuel," Richter says. "And because there isn't enough agricultural land in the world basically you have to expand into previously untouched habitats, which is forests, grasslands and so on."

"This means that you get deforestation and land rights conflicts in many countries," Richter added. "The large scale use of biofuels in aviation is unsustainable as it relies on the same food crops already being used in biofuels for cars, contributing to rising food prices and deforestation. "

So if current biofuels are not the answer, what hope is there for the next generation?

"Second generation crops are where people are looking at breaking down woody products into fuel or possibly waste products into fuels," said Melanie Coath, a senior climate change policy officer for the RSPB. "But the same land use problems still apply, because if you're planting trees you're still going to be displacing whatever the land use was, so that could still be a problem."

According to Coath, Waste products are a better choice but they have limited availability. Worse still, the technology to produce them is not currently commercially viable. "They've been saying for years that it's five or 10 years away from being commercial viable. The technology exists, it's just really expensive."

Even further into the future there is the possibility that biofuels may be produced using fats of algae, grown under artificial or natural lights. Again, commercial viability remains the critical factor.

"You can imagine having big fats in a sunny desert where you don't have the same land use impact, because there is no existing carbon land use there. That could be exciting, but at the moment it is still too expensive and is only commercially viable for producing pharmaceuticals."

So what is next? For now campaigners agree that caution is key. Airlines such as Thomson should be applauded for trying to prove the case for biofuels in the future. However, excitement must be tempered with realism.

As Coath concludes: "We need to be really careful about portraying biofuels as green because some of them can be and some of them can be exactly the opposite."