The hidden costs of biofuels

Are biofuels all they're cracked up to be? (Image:iStockphoto)

Concerns that the health and environmental impacts of biofuels haven't been properly examined have arisen following a recent Australian government report and a pledge to promote their use.

The Report of the Biofuels Taskforce to the Prime Minister released last week found that the government's own targets on producing biofuels, namely ethanol and biodiesel, aren't being met.

And the Australian government has promised to do more to reach its target of producing 350 megalitres of biofuels a year by 2010.

But not everyone agrees that biofuels are the hoped-for magic bullet as an alternative to fossil fuels.

One of them, environmental engineer and pollution expert Dr Robert Niven of the University of New South Wales in Sydney, says his research shows ethanol may increase groundwater contamination and photochemical smog.

"It's sort of entered the mythology," he says of the claimed benefits of ethanol, admitting his findings about air pollution, published in Renewable and Sustainable Energy Reviews this year, came as a surprise.

The ethanol debate
Ethanol, which is distilled from sugar or grains, can be used on its own or added to petrol to increase combustion efficiency and cut back emissions.

Niven says the report glosses over the environmental consequences of ethanol.

He says ethanol can increase corrosion of underground petrol storage tanks, leading to increased leakage.

And once a leak has occurred the ethanol prevents biodegradation of the petroleum because the microbes that normally attack the petrol go for the ethanol instead.

"These effects work against the ability of the natural environment to restore itself," he says.

Niven also says ethanol produces higher volatile emissions through evaporation and more nitrogen oxide emissions compared with fossil fuels.

Together these produce photochemical smog, or ground level ozone, the cause of the "brown haze" that sometimes shrouds Australia's most populous city Sydney.

Reducing greenhouse gas emissions?
CSIRO Low Emissions Transport leader Dr David Lamb says ethanol may help society "escape from the tyranny of oil", but its benefits in terms of reducing greenhouse gas emissions, in particular carbon dioxide (CO2), are small in the scheme of things.

"We measure the CO2 used in fertilising the crop, plus transportation, plus machinery, plus when you burn it in the car," says.

"We add that up and offset it against the CO2 absorbed by the sugar cane when it's growing and the answer is it's a little bit favourable."

And while he says he hasn't seen anything to suggest ethanol increases particulates in exhaust more tests are needed.

He says every litre of fossil fuel burnt puts 2.3 kilograms of CO2 into the atmosphere, which translates to an average of 4.3 tonnes of CO2 for every car in the world, every year.

Some research suggests ethanol may contribute to photochemical smog (Image: Reuters/Carlo Cortes)