Next generation of liquid biofuel production

Abstract

More than 99% of all currently produced biofuels are classified as “first generation” (i.e. fuels produced primarily from cereals, grains, sugar crops and oil seeds) (IEA, 2008b). “Second generation” or “next generation” biofuels, on the other hand, are produced from lignocellulosic feedstocks such as agricultural and forest residues, as well as purpose-grown energy crops such as vegetative grasses and short rotation forests (SRF). These feedstocks largely consist of cellulose, hemicellulose and lignin. Conversion to bioethanol fuel is via hydrolysis of the cellulose and hemicellulose to sugar, after which fermentation of sugar is performed. These feedstocks can also be converted to fuel via gasification or pyrolysis to produce synthetic diesel, bio-oil and other fuels. To be competitive with fossil fuels, there is a need to overcome several technical challenges – which is the focus of current R&D. Generally, the advantage of next generation biofuels (over 1st generation biofuels) is their ability to utilise many different types of lignocellulosic materials as feedstock and lower land use impacts. However, the environmental impact of lignocellulosic biofuels depends on the conversion route, the feedstock and site-specific conditions. Moreover, unlike the mature 1st generation biofuels, next generation biofuel technologies are still under devel-opment (pilot and demonstration stages), and commercialisation is anticipated in the next decade. This section analyses the short term and long term technical and economic performance as well as the potential development of next generation biofuel industries in five develop-ing countries under some defined settings.