A quick guide to biofuels

The schoolboy joke about his cycle going faster if he eats beans is getting closer to reality - and beans could play a part in it. But it is not wind-power but another type of renewable energy that is in prospect.

Beans, sunflower seeds, grain - they can all help. These are the basis of Europe’s nascent biofuel revolution. Instead of vehicles running on expensive imports of fossil fuels, the aim is to power them with derivatives of crops and other natural substances. Biofuel advocates claim that sustainable and innovative technologies will soon be delivering products that are clean, secure, CO2-efficient and affordable.

But there are some major challenges to be met. It is going to need big investments in generating and harvesting the right raw materials, perfecting the technology for their commercial transformation and in processing them to agreed standards.

The new fuels will have to be compatible with today’s fuel types, distribution systems and vehicles. The concept will take much longer to arrive if new engines are going to be needed, or if filling stations and fuel depots have to be retrofitted. It will not work if it is going to steal land currently used for growing food, either, or if the processing is going to be too expensive, or pump out excessive greenhouse gases.

So far, commercial EU operators are transforming wheat and sugar beet into ethanol, a fuel that can be used directly in specially-adapted vehicles, and - more significantly - can be processed as an additive to gasoline (ethyl tertiary butyl ether) which can be used without the need to modify engines.

Biodiesel is also being produced in the EU from oil-seed crops (notably rapeseed, sunflower, and soy bean), which are converted into fatty acid methyl esters. More than 1,500 German service stations sell pure biodiesel - but it too is mostly used as a low-concentration blend with conventional diesel.

There is also a niche market for compressed biogas (led by Sweden), whether produced in dedicated facilities from organic wastes, or recovered from municipal solid waste landfills - a method which has the added advantage of cutting greenhouse gas emissions.

But for biofuels to come of age they need more raw materials, smarter technology and large-scale refineries.

One of the short-term priorities is to permit a wider range of feedstocks to be used. Optimists predict that within a decade, the biotechnology industry will have created custom-designed high-yield low-input energy crops that can grow on marginal land and ease conflicts with the food chain.

But the key will be technologies that can efficiently convert intractable natural products such as cellulose and lignin into the sugars that in turn are refined into fuel. This would open the door to wide exploitation of plentiful biomass - not just wood and straw, but even waste materials. A combination of smarter processing and crop design will also reduce vehicle emissions of greenhouse gases from these so-called second-generation biofuels. Lower costs in CO2-avoidance and carbon sequestered by dedicated energy crops could eventually provide a net greenhouse gas benefit.

Technology is meanwhile helping to overcome some of the downsides of current biofuels. DuPont and BP will this year launch biobutanol - developed to give better fuel economy, be more tolerant of co-existence with water contamination in gasoline mixtures and capable of blending into gasoline at higher concentrations than other current biofuels.

Current methods of converting ethanol into ethyl tertiary butyl ether require iso-butene, an often-scarce by-product of conventional refinery processes, which also carries a risk of contaminating groundwater. Biodiesel is produced at present using a fossil-fuel derivative, methanol. But now there are growing possibilities of using biomethanol, or even producing fatty acid ethyl ester bioethanol, which could allow oils of biological origin to generate biofuels fully independent of fossil fuels.

To achieve commercially viable volumes, appropriate refining capacity will also be needed, integrating biochemical and thermochemical transformation stages in the same installations, right through to final recovery and purification of the product. But the required flexibility - to say nothing of the sophistication and control that has taken so long to build up in the chemical industry - will not be acquired overnight.

Nonetheless, the possibility of motoring along on a kilo of beans is not that far away - and it will not be necessary to open your window either.

• Peter O’Donnell is a freelance journalist based in Brussels.

The schoolboy joke about his cycle going faster if he eats beans is getting closer to reality - and beans could play a part in it. But it is not wind-power but another type of renewable energy that is in prospect.

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