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  Riverford sustainable development project


'food miles' - the knotty question of biofuels

biofuels for transport

Burning conventional fuels releases fossil carbon into the atmosphere that has not been part of the carbon cycle for millions of years; as a result there is more CO2 in the atmosphere than the current carbon cycle can deal with.  This results in an increase in atmospheric CO2 and a net contribution to climate change.


Biofuels are transport fuels produced from recently grown crops, this means when they are burnt they release CO2 emissions that were recently removed from the atmosphere during the growth of the crop and so are, in theory, ‘carbon neutral’.  This is not quite the case, as fossil fuels are still required in their production; to produce fertilizer for, farm, harvest and process the crop into useable fuel.  On top of this are the issues associated with the land used to grow the crop.  If land is being converted from food production to fuel production this reduces world production of food and raises the wholesale price of foodstuffs.  Land could also have been acting as a long term carbon store, as is the case for rainforests which are being cut down to provide land for fuel, or food that has been displaced by fuel production elsewhere.


From a practical perspective biofuels fall into the following groups


  1. converting waste into fuel; the best, most publicised and sensible example being the use of waste oil from commercial kitchens for use in diesel engines after a relatively simple conversion process. Claims are made that waste from food crops, having extracted the valuable food element, can also be used but there seem to be few examples of this in practice.  There is also a renewed interest in biofuel production from tallow, a by-product of meat rendering.

  1. growing crops specifically for conversion into bio-diesel and ethanol. About three years ago we did some research and considered installing a plant to convert chip-fat to diesel. It took less than a week to reach the conclusion that the benefit to the world would be small if any. Most easily available used oil was already being used (either by existing converters or being burnt in power stations) and palm oil was already being imported to turn into diesel. Even without considering the pressure on world food supplies, deforestation and wildlife, the equation of energy in to energy out is poor for temperate oil crops like rape. If it is so easy to reach this conclusion why it is that bio-fuels have formed a central plank in so many companies’ corporate responsibility claims (Tesco, Virgin, and indeed our government)? I can only conclude that either they could not be bothered to do the most rudimentary research or they are more consumed with currying short term approval than achieving true responsibility; perhaps a bit of both. The annoying thing is that spin works; according to a report on corporate responsibility Virgin is in the top six brands in terms of respect for environmental values.

As of this April fuel suppliers in the UK will be committed to the Renewable Transport Fuel Obligation (RTFO). This is a government objective that aims to have 5% of fuel sold on forecourts to be obtained from biofuels, of the second type described above, and tallow-derived, by 2010.  Working on an average CO2 saving of 50% by using biofuels the government hopes to achieve a 2.5% reduction in transport related CO2 emissions. 


However, much information has come to light recently that questions the real benefits of biofuels due to knock on effects on world commodity prices and the potential for the destruction of long term carbon stores such as rainforest as they are converted for growing biofuel feedstock.  As a result of this there is no consensus on the sustainability of biofuels and the government has initiated a review of available information, the results of which are due in June.


Up to date information regarding government policy and research can be found here on the defra web pages.