Biofuels

Biofuels Oilseed rape - commonly grown for the production of biodiesel. © ClemRutter.

By Martyn Poliakoff FRS

Why do we need biofuels?

Oil is running out. In the short term it will continue to go up in price and in the middle distant future it will be too expensive to burn. The use of biofuels will help extend the life time of our oil supply, but eventually we will need to replace oil – whatever that replacement is it needs to be sustainable.

What is the main advantage of using biofuels?

Plants grow by absorbing carbon dioxide from the atmosphere; if we turn plant material into fuel, we return that carbon dioxide to the atmosphere when we burn the fuel - so there is no net increase.

What are some of the disadvantages?

There are a number of problems with burning biofuels in road vehicles. The fuel must not damage a vehicle’s engine - cars are designed to use a specific fuel (like petrol), but not necessarily biofuels. One moral issue is that today’s first generation biofuels come from crops that could be used for food. It is expected that – possibly quite soon - we will develop second generation biofuels for cellulose, the parts of plants you can’t digest unless you’re a rabbit - and they have to eat it twice! Also, you can’t travel as far on a litre of biofuel as it contains more oxygen than normal fuels do.

Are biofuels the answer to future oil shortages?

In the long term I don’t think that biofuels are a sensible way for powering road transport - eventually hydrogen or electricity is likely to be much more efficient. Biofuels are more suitable as a short term supplement to oil usage than as a long term replacement.

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Martyn Polyiakoff FRS also discusses the power of plants in this short video.