INSIGHT: Can biofuels from crops be made viable?

25 October 2006 15:17  [Source: ICIS news]

By Simon Robinson

LONDON (ICIS news)--Using biological sources to produce fuels -biofuels- poses several conundrums that the world will have to face if these innovative sources of energy are to really replace oil.

As I see it the major areas of conflict in the biofuels hypothesis, revolve around at least three areas: volume, water, and tax treatment of biofuel projects. I’m going to look at one of these here, but the others are themes in my web-based exploration of this subject, which you can find at the Big Biofuels Blog .

It looks like the yield of crops has to increase dramatically for biofuels to make sense. Using conventional fermentation technology around three tonnes of wheat produces one tonne of bioethanol.

Part of the reason that yields are so poor is because only the grain is used in fermentation, rather than the whole wheat, from seed to root. This level of ethanol production is probably only sustainable in fairly limited quantities of bioethanol production because of the strain it would put on world food supplies.

Based on data on US gasoline consumption for September this year and converted this to tonnes/year using a rule of thumb of one barrel/day this equates to around 50 tonnes/year of demand. Using September as an average, then the US will use between 462m tonnes and 472m tonnes annually.

The US Department of Agriculture (USDA estimates) in its March 2006 year book that this year there will be 41m US acres of wheat cultivation , producing around 2105m bushels which is equivalent to 57m tonnes of grain .

Even if we malted, brewed and distilled all of this, we’re talking about 19m tonnes ethanol. Ignoring the difference in energy produced by one tonne ethanol and one tonne gasoline, that’s not quite enough volume to make a 5% blend with gasoline.

So the US couldn’t at the moment move to E95 - a fuel containing a mixture of 95% ethanol and 5% gasoline - if it were prepared to stop eating wheat, and to stop using any excess to support UN food relief operations, for example.

So what about biofuels from food oils?  Even if we diverted the whole world's supply of vegetable oil  estimated at 106.82m tonnes in 2005, by the USDA, we’re still going to be way short. That’s assuming that it is a  replacement for gasoline, which it isn’t.

These shortfalls explain why people are interested in using the whole of the wheat from the seed to the root or the whole of anything else that grows quickly. There is a lot of talk about switch grass and other weeds that could be converted to fuels.

Some are arguing that if we could find a way of converting the complex cellulose chemicals that plants use in their skeletons as they grow into sugars or directly to fuels the world would be able to breathe again.

Counter arguments are running about the viability of this approach and whether we’d be better off burning them and generating electricity from the steam you could make.

This is something I’ll be blogging about in the Big Biofuels Blog, along with the paradox of a set of bioproducts that will rely on fossil fuel-produced fertiliser to maintain production levels.

But that and energy conservation in the West are different stories.

Simon Robinson has started a blog on biofuels for ICIS.

By: Simon Robinson
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