To assess which biofuels have the better potential for the short-term or the longer term (2030), and what developments are necessary to improve the performance of biofuels, the production of four promising biofuels-methanol, ethanol, hydrogen, and synthetic diesel-is systematically analysed. This present paper summarises, normalises and compares earlier reported work. First, the key technologies for the production of these fuels, such as gasification, gas processing, synthesis, hydrolysis, and fermentation, and their improvement options are studied and modelled. Then, the production facility's technological and economic performance is analysed, applying variations in technology and scale. Finally, likely biofuels chains (including distribution to cars, and end-use) are compared on an equal economic basis, such as costs per kilometre driven. Production costs of these fuels range 16-22 EURO/GJ(HHV) now, down to 9-13 EURO/GJ(HHV) in future (2030). This performance assumes both certain technological developments as well as the availability of biomass at 3 EURO/GJ(HHV). The feedstock costs strongly influence the resulting biofuel costs by 2-3 EURO/GJ(fuel) for each EURO/GJHHV feedstock difference. In biomass producing regions such as Latin America or the former USSR, the four fuels could be produced at 7-11 EURO/GJ(HHV) compared to diesel and gasoline costs of 7 and 8 EURO/GJ (excluding distribution, excise and VAT; at crude oil prices of similar to 35 EURO/bbl or 5.7 EURO/GJ). The uncertainties in the biofuels production costs of the four selected biofuels are 15-30%. When applied in cars, biofuels have driving costs in ICEVs of about 0.18-0.24 EURO/km now (fuel excise duty and VAT excluded) and may be about 0.18 in future. The cars' contribution to these costs is much larger than the fuels' contribution. Large-scale gasification, thorough gas cleaning, and micro-biological processes for hydrolysis and fermentation are key major fields for RD&D efforts, next to consistent market development and larger scale deployment of those technologies. (c) 2005 Elsevier Ltd. All rights reserved.