What are biofuels?
Biofuels are any liquid, solid or gaseous fuels produced from organic matter. The extensive range of organic materials used for biofuel production includes starch and sugary plants such as corn, wheat or sugar cane; oily plants such as rape seed, soya beans or jatropha; vegetable oils and animal fats; wood and straw; algae and organic waste and others. Biofuels are commonly referred to as first generation, mainly bioethanol and biodiesel, or second generation, which cover a variety of technologies currently in the pipeline.
In the wake of environmental concerns and volatility of oil supply the development of alternative fuels is crucial to the future of the transport sector. This need has been widely recognized by policy makers and resulted in the introduction of European Biofuel Directive in 2003 and UK Road Transport Fuel Obligation in 2008. Both documents call for 5% biofuel blends with fossil fuels by 2010. Currently biofuels substitute around 2.6% of all transport fuels sold in the UK.
Not a new technology
Biofuels are not a recent invention and have a long history in the motor industry, stretching right back to the development of the internal combustion engines of the 1800s. Rudolf Diesel designed his compression engine to run on peanut oil, while Nicolaus Otto’s pioneering spark-ignition engine was developed to run on ethanol. The case for bioethanol was in particular championed by Henry Ford who had a vision to “build a vehicle affordable to the working family and powered by a fuel that would boost the rural farm economy”. He himself also owned an ethanol plant and his famous mass produced Model T Ford first ran on bioethanol.
First generation biofuels
The two most common 1st generation biofuels are bioethanol from starch or sugar crops and biodiesel from oil-rich plants. As these fuels are primarily derived from crops which may also be used as food for animals and humans, these type of fuels have been criticised for diverting food away from the human food chain to the engine. Biofuels’ impact on the environment and food prices and sustainability of production are often scrutinized in mass media. Research in the field suggests however, that whilst still depending on method of production, the overall green house gas emission savings are positive and in some cases zero carbon production is possible as carbon emitted during the burning of biofuels is compensated by the carbon absorbed by the plants as they grow. Impact on biodiversity may be negative, however, in many cases the cultivation of biofuels may enhance biodiversity, especially if underutilized agricultural land is used for production. Biofuels will only negatively impact food markets if they compete for land with the agricultural sector.
Second generation biofuels
Second generation biofuels are broadly speaking the biofuel technologies still in the pipeline. It is these sustainable biofuels that will provide the source for the future. Some of the new technologies focus on increasing yields from plant-derived fuels; others look at the application of microbiological research to improve energy efficiency and range of renewable feedstocks for biofuel production. The Biofuel Research Centre focuses on 2nd Generation biofuels produced by microbial fermentation of non-food crops. These carbon-rich lignocellulosic materials are renewable and widely available. Sources include agricultural waste such as corn stover, straw and bagasse; industrial waste such as sawdust and paper pulp; woody biomass from forestry; municipal solid waste including household food and garden waste and paper products; and specific non-food energy crops such as switchgrass. Conversion of lignocellulosic biomass is attractive and even more so if biomass which is otherwise regarded as waste can be used as the substrate. In this case, the overall energy yield and carbon footprint will be improved compared to first generation biofuels as there is no need to cultivate and harvest the crops. How we best harness this energy stored within lignocelluloses may provide the solution for biofuels in the future.