What has sustainability got to do with… biofuels?

Are they the carbon-neutral fuel that never runs dry? Or “deforestation diesel”, wiping out orang-utans and trashing pristine habitats? Hannah Bullock filters out the facts.

What are biofuels anyway?

Corn, soya beans, rapeseed, sugarcane, palm oil - if you can refine or ferment it, it can be turned into fuel.

Are they really carbon neutral?

Yes and no. Burning them produces CO2 and other greenhouse gases - but not as much as petrol. And since they absorb the same amount when they’re growing, they’re a closed carbon loop - in theory

Can you breathe easier?

On the whole, yes: compared to petrol or diesel, they emit fewer pollutants like sulphur dioxide, carbon monoxide, particulates and unburnt hydrocarbons. But they puff out 10% more nitrogen oxide (the main culprit in acid rain).

Who’s on the biofuel bandwagon?

The US - big time. Bioethanol is good news for its corn industry, so Bush wants it to replace up to 15% of the country’s petrol sales over the next decade. The EU has stipulated that biofuels must make up 10% of transport fuels by 2020, and the UK has a target of 33% by 2050.

Pretty ambitious stuff. Can it be done?

Well, there is a limit. It’s unlikely we can produce enough to fuel transport the world over. We’d need around 9% of the planet’s agricultural land to provide just 10% of global transport fuel. And one sobering estimate suggests the same amount of grain that goes into producing a tankful of ethanol for a Range Rover would feed one person for an entire year.

So it’s a fuel versus food thing?

Versus forests, too. If you’re clearing trees to make way for palm oil, it’s not just the orang-utans we’re losing, but our vital carbon sinks. Burning Indonesian forests to grow enough oil palms for one ton of fuel releases 33 tons of carbon - ten times that emitted from burning the same amount of petrol.

So why not grow it on land no one wants?

That’s what gets people excited about hardy plants like prairie grasses - and jatropha [below] - plugged as ‘green gold’ for India’s wastelands. Optimists conjure up images of the country’s vast rail network lined with jatropha bushes. Its seeds are high in oil that’s easy to refine. But the more profitable biofuels get, the more likely these crops are to ‘spill out’ onto vast plantations, needing a whole load of energy, water and pesticides to cultivate, distil and transport them. And the fear is that, where biofuels do compete with food crops, the land will go where the money is.

Er, should we just stick with petrol, then?

No, we shouldn’t throw the baby out with the bathwater. There are ways of getting more out of plant power...

•  Local growth, local use: The Pacific island of Bougainville weaned itself off imported diesel and onto coconut oil fuel. It makes sense to keep it close to home. Imagine British farmers driving tractors running on locally refined rapeseed oil.
•  Easy on the forests: The Brazilians have got it right, where São Paulo sugar cane farmers must leave a percentage of their land as natural reserves.
•  More bang per buck: Cereals such as maize have been bred for centuries to maximise their food value. Breed them for oil content, and their fuel potential could soar. Microbiologists are also exploring getting a higher calorific product - such as butanol - as the end outcome.
•  Use it all: Biofuels are traditionally made of just the sugary bit of cane or the corny bit of maize. The newest methods use the stem as well, and the most efficient harness the woody leftovers to drive the distillation process. Such ‘cellulosic’ biofuels could even mean a single crop could be used for both food and fuel. Don’t forget the waste gases, rich in hydrogen - a precious fuel source itself. But that’s a whole other story...

24 June 2007

Hannah Bullock