The trouble with biofuels


Canola can be used as a biofuel.

Credit: istockphoto

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Second Generation

Using vegetable oils to run diesel plants is now being encouraged in many other isolated parts of the world by groups such as the Porter Institute: in Tuvalu and in countries such as Malawi and Zambia where scientists are working on projects that will use groundnut (peanut) oil to provide electricity.

But the potential for biofuels goes beyond their opportunistic use in remote places, say enthusiasts. They point to new generations which pose far less of a climatic threat than current versions, which don't require the carbon dioxide-intense practices of growing of other crops.

First-generation biofuels use easily accessed starches as their basic ingredient. But now, scientists are working on ways to ferment ethanol from tougher ingredients: corn husks, grasses and other inedible forms of vegetation high in cellulose, the sturdy material found in stalks and leaves.

The trick is to break down a plant's lignin, an organic polymer which binds to cellulose, the sturdy material that helps plants keep their shape.

Cellulose can be broken down and used as an ingredient for fermenting, but the process is complex, requiring an assortment of enzymes. More than 80 research centres in Australia and overseas are now testing new enzymes that would thus be able to break down stubble, corn stover (the leaves and stalk left after harvest), wood chips and other agricultural waste and help release sugars which would otherwise be unavailable for fermenting.

Researchers at Australia's Monash University have developed a chemical process, called Furafuel, that turns agricultural waste - such as forest thinnings, crop residues, waste paper, and garden waste which are normally dumped in landfill or burned - into biofuel, either ethanol or biodiesel.

"We've been able to create a concentrated biocrude which is much more stable than that achieved elsewhere in the world," says Steven Loffler, senior researcher at Australia's national science agency, the CSIRO.

"By using waste, our Furafuel technology overcomes the food-versus-fuel debate, which surrounds biofuels generated from grains, corn and sugar."

Thus, biofuels could soon be made from plants that thrive in marginal farmland, negating the need to displace food crops.

Of course, such scenarios are a long way from the image of golden crops swaying in the sun ready to provide carbon-neutral fuels for cars being driven in the streets.

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