Problems with biofuels

The main biofuels are ethanol and biodiesel, which are becoming used more frequently in an effort to slow down global warming. Germany, for example, aims to provide 17% of its liquid fuel need from biodiesel and ethanol within ten years.

I have already written about corn being used to provide ethanol and the research shows that this is in fact more productive of carbon dioxide, when taken over the whole life cycle, than drilling for and using oil. The thermodynamics of ethanol from corn production shows that.

Biofuels are no silver bullet. They are, like fossil fuels, burnt and the burning produces greenhouse gas emissions. The theory behind growing energy instead of drilling or mining for energy is that once grown it can be grown – in that sense it is reasonably “sustainable” in terms of supply, but that does not mean that biofuels are sustainable in the current understanding and usage of the word. One person’s sustainability is another person’s deprivation when biofuels are used. It may be sustainable for the well fed rich but it is far from sustainable for the badly fed poor.

Oil, gas and coal have very high masses when compared to their energy content, because of the fossilisation process which concentrates the mass but retains the energy or calorific content. Plants have very low energy content in terms of their mass, so that biofuels require huge areas of cultivation to produce a fuel which is concentrated and can be used like diesel or petroleum. This means that the processing of biofuels tends to be very energy intensive, and this intensity – farming, fertilising, cropping and processing all requiring quite large amounst of energy, in some cases quite as much as the energy produced by the end product of the farming.

There are also implications for feeding the world. Corn prices were driven very high as corn was diverted from human consumption to fuel consumption.To roduce 50 litres of ethanol from corn, which would in an average car be used in 350 miles of travelling, needs 232 kilos of corn, which is a lot of bread, tortillas, and other food.

Professor Hartmut Michel, a Nobel Prize winner in biochemistry points out that biogas, when produced from anaerobic digestion of corn ends up providing 2 kilowatts of continuous power per hectare, which after taking into account the energy cost of production reduces to just over half. Germany might find that it does not have enough land to reach a biogas target of even 10%.

There are similar problems with rapeseed oil which yields about 1200 litres per hectare but uses 62% of the energy in producing the biodiesel. Yielding biomass into liquid to meet the Germany 17% target, professor Michel calculates, would need a fifth of Germany’s land mass.

So it seems that biomass fuels compete with food production and send the food costs higher. The perceived benefits are largely illusory.

4 Responses

  1. Robert – The underlying theme of your blog is that many alternative ways of producing energy, aren’t necessarily that good at producing energy or clean either.

    I know you’re objective and impartial and provide a balanced opinion to this subject.

    My question is this: why do you think, in the face of such evidence, there is so much resistance to harvesting solar energy? When it seems like the best alternative by a country mile.

    Respect and Peace!
    @dam

  2. I’ve heard you say this before, but how can there be more backing for biofuels over solar power? It seems crazy. What can / needs be done to change this situation?

    Respect and Peace!
    @dam

  3. I cannot believe a learned person came out with such an answer Robert, as many people know poloticians are now and have always been in the pockets of who ever pays them the most benefits from society and what nature has to offer.

    Energy in what ever form that runs our needs and on top spot will never ever give up its monopoly for any another form until it has exhausted the current one, even if it is going to be the eventual winner and long term cleaner alternative.

    As a collection of carbon units we are on the whole rather stupid at wanting to pay to polute, but again the leading pollouters will simply continue to do so until such a time we the people want the changes we all want to see.

    But don’t bank on things changing soon, once there is a majority rule the national grid will stay exactly as it is, our needs right now are for power at what ever cost it is to us all.

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