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SCI debates biofuels

Carlos Harrison

The 2008 spike in fuel prices, combined with sky-high food inflation, makes it easy to see why biofuels has become one of the most hotly debated issues of our time.

The subject not only raises very strong views – with opinion sharply dividing into two distinct camps – but has also 'fuelled' a raging debate. One side blames biofuels for diverting land away from crops for food to crops for biofuels, and the other arguing that there is ample land for both with better innovation and technology.

The Biofuels: Technology meets Strategy conference held on 20 May 2008 was organised by the Process Engineering Group (PEG) to address these and other issues, together with the pros and cons, challenges and opportunities for the bioethanol, biodiesel and biomass industries.

Key topics included:

  • The importance of non-food oil crops for the biodiesel industry
  • The production of bioethanol – either by synthesis from syngas (obtained by gasification from biomass), hydrolysis-fermentation of lignocellulosic materials or the fermentation of sugars
  • The potential of computational metabolic engineering to improve the yield of bioethanol production from fermentation by yeast
  • The UK government’s Renewable Transport Fuel Obligation (RTFO) which came into effect in April 2008.

Other topics under discussion also included the implications for the motor industry and policy makers, for example, biofuels are currently being blended into petrol and diesel which are sold in petrol stations so some of us actually may be using them without knowing. And biofuel consumption is expected to grow.

During the seminar, Professor Graeme Walker, from the University of Abertay, rightly pointed out that biofuels is not new. The Model T Ford released in 1908 was originally designed to run with bioethanol. He also commented on the advantages of bioethanol as an option to reduce dependence on fossil oil and a way to reduce GHG emissions. With blends containing about ~10% v/v, Brazil and the US are leading the production of bioethanol. In contrast, Europe’s bioethanol production is lagging behind.

Professor Walker presented his work on bioethanol production by yeast fermentation and explained that bioethanol from lignocellulosic and from spent grains feedstocks is the future of bioethanol production.

Dr Brian Dobson talked about the importance of non-food oil crops for the biodiesel industry, non-food oil meaning oil which is toxic to humans.

He pointed out that the specific parameter to avoid the food-fuel and rain forest destruction debates is the use of unproductive land with low biodiversity to grow high yield non-food fuel crops; vegetable oil from Jatropha being a good option. He explained that current technology is based on production of Fatty Acid Methyl Ester (FAME) and the second generation of biodiesel production technology, like vegetable oil hydrosplitting/ hydroisomerisation, is the way forward.

Professor Tony Bridgwater, from Aston University, explained that bioethanol from biomass could be produced either by synthesis from syngas obtained by gasification or by fermentation from either syngas from gasification or sugars from hydrolysis. Other sources of biofuels are the so-called ‘hydrocarbons’ which are produced from thermal biomass gasification and undergoing further synthesis (e.g. Fisher-Tropsch or methanol synthesis). Professor Bridgwater explained that in situ fast pyrolysis is a suitable pre-treatment that allows fast mobility of biomass and its centralised gasification and synthesis.

Another option for biomass processing is the hydro-processing of vegetable oil. Professor Bridgewater went on to describe how all these technologies are leading to the concept of biorefineries, where the production of high value chemicals is integrated with the optimised use of resources and fuel and energy consumption to maximise profitability and minimise waste.

Later on the day, Dr Steve Wilkinson, from the University of Manchester, explained the potential of computational metabolic engineering to suggest genetic modifications to metabolic pathways which would improve the yield of bioethanol production from fermentation by yeast. His approach is to develop a computational model to estimate the effect of certain genetic manipulations using metabolic control analysis as a tool. This analysis relies on the solution of ordinary differential equations and their resulting integration which is then compared with experimental results to validate those assumptions. With the effects of the original genetic modifications understood, a new set of proposed modifications is set and the process is repeated until optimum yield is reached. As an example, Dr Wilkinson showed the methodology applied to the production of biobutanol from fermentation by E. coli which reaches an 86% of theoretical maximum.

However the introduction of biofuels into the road transport system is far from simple, argued David Lemon from David Lemon Consultants.

He said: 'Some engines accept only blends of up to 10%. For a higher content of biofuel in our car tanks most engines have to be modified. Although some fuels like biodiesel, bioethanol and biobutanol might be used directly in currently available engines and blends, some other biofuels cannot be readily fed into modern engines without modification. These are biogas, DME, methanol and hydrogen.'

He also pointed out that the car is one of the least efficient ways to travel (CO2 wise) while the underground and train are the most efficient. He also explained that the Bus Service Operators’ Grant is a barrier to the introduction of low carbon emission buses in the UK because it does not reward improved fuel economy. One of the important conclusions of the King Review pointed out by Mr Lemon was that transport is one of the least cost-effective uses of biomass in saving CO2; a better option would be heat and power.

In the final talk of the day, Mr Howard Emmens from the Department for Transport explained that the UK government is concerned about climate change by CO2 emissions, currently setting the frame for a 26% reduction by 2020 (against a 1990 baseline). This led the British government to enact the Renewable Transport Fuel Obligation (RTFO) which came into effect in April 2008. Mr Emmens explained that this obligation requires that all suppliers of fossil transport fuels to sell at least 2.5% of renewable transport fuel of the total fuel sales each year; this created a demand of 2.5 billion litres of biofuels a year. The RTFO is based on the concept of ‘carbon savings and sustainability’. The principles behind RTFO are environmental and social. Mr Emmens commented that at EU level the picture is similar; the Renewable Energy Directive target is 13% v/v biofuels by 2020 where production shall be sustainable and based on 2nd generation biofuels.

At the end of the seminar there was an opportunity for networking and further discussion with the speakers over a glass of wine.

The mood was animated as established academics swapped ideas with younger researchers. Even more importantly, industrial delegates involved with designing new biofuel plants were able to talk directly to those in the civil service implementing the government's strategic biofuels policy. The fact that these discussions were carried on in a local pub shows how stimulating the whole day had been.

The committee of the Process Engineering Group would like to give a huge vote of thanks to its new Chairman, Carlos Harrison (pictured), whose hard work and large contact book made the meeting such a roaring success.

Organised by the SCI Process Engineering Group

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