Sugar-power cars 'could sort out pollution'Scientists find way to produce cheap, green fuel

10 April 2008

A spoon of sugar

Sugar-powered cars could be the sweet solution to traffic pollution, say scientists.

Researchers have found a way to generate hydrogen directly from plant sugar.

They expect the breakthrough to provide a cheap and efficient source of green transport fuel.

Plant sugars

In future, motorists could be stopping at grocery stores instead of petrol stations to fill up on packets of solid starch or cellulose, say the scientists.

The new process involves combining plant sugars, water, and a cocktail of powerful enzymes - biological catalysts - to produce hydrogen and carbon dioxide.

It overcomes three major hurdles standing in the way of replacing fossil fuels with hydrogen, according to the researchers.

Hydrogen economy

How to generate low-cost sustainable hydrogen, store the gas, and distribute it efficiently are all obstacles holding back a move to the 'hydrogen economy'.

Biochemical engineer Dr Percival Zhang, who leads the development team at Virginia Polytechnic Institute and State University in Blacksburg, US, said: 'This is revolutionary work. This has opened up a whole new direction in hydrogen research. With technology improvement, sugar-powered vehicles could come true eventually.'

Current biofuels consist of ethanol made by fermenting plant material and combustible plant oils. They are burned in traditional internal combustion engines as alternatives to petrol and diesel.

Fuel cells

Plant-derived hydrogen, on the other hand, could provide a more environmentally friendly fuel cell power source.

Fuel cells produce electricity by combining hydrogen and oxygen from the air, without 'going dead' like conventional batteries. The only waste products are water and small amounts of carbon dioxide.

However making hydrogen is expensive and inefficient. Most commercial production methods rely on fossil fuels, such as natural gas, while newer innovations yield low levels of hydrogen. Researchers worldwide are urgently looking for better ways to produce hydrogen.

Reactor

Dr Zhang's team collected 13 different well known enzymes and combined them with water and starches in a specially-designed reactor. Heated to a moderate 30C, the resulting broth generated hydrogen and carbon dioxide with no leftover pollutants.

The scientists, who described their research today at the annual meeting of the American Chemical Society in New Orleans, are now working to make the process faster and more efficient. At present the amount of hydrogen produced is still too low for commercial applications.

One approach is to find enzymes that work at higher temperatures, to speed up hydrogen production. The researchers also hope to generate hydrogen from cellulose instead of starch.

Safe

A sugar-fuelled car would be inherently safe because its hydrogen is used immediately, said Dr Zhang. He added that it would also be cheaper and cleaner to run than even the most efficient petrol-driven car.

As an alternative to cars generating their own hydrogen, the technology could be used to develop an infrastructure of hydrogen-filling stations.

The first vehicles running on hydrogen made from plant sugar could be on the road in eight to 10 years, said Dr Zhang.

Scaled-down versions of the technology could be powering portable music players, mobile phones and laptops in about half that amount of time, he estimates.

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