Comprehensive techno-economic assessment of dimethyl ether (DME) synthesis and Fischer-Tropsch synthesis as alternative process steps within biomass-to-liquid production

The conversion of lignocellulosic biomass, such as residual wood or straw, to synthetic fuels and chemicals is currently being developed within the bioliq (R) concept. The aim of this study is to model and assess two different biomass-to-liquid (BtL) concepts for the production of gasoline via dimethyl ether (DME) synthesis as well as gasoline and diesel via Fischer-Tropsch (FT) synthesis. The techno-economic assessment concludes that total energy efficiencies from biomass to final products range between 38 and 39%. The resulting production costs of gasoline via DME synthesis are about 1.15 (sic)/L (0.82 US$/L). Gasoline and diesel via FT synthesis can be produced at costs of about 1.23 (sic)/L (0.88 US$/L). The production costs for biomass-derived fuels are 76 to 93% higher than current market prices. However, the considered technologies are close to becoming competitive to conventional refineries since the production costs are only 7 to 18% higher than current market prices when coal is used as main feedstock. Further, the implications of negative CO2 emissions, mineral oil tax reduction and the combination of both kinds of subsidies in order to compensate high biomass feedstock costs as well as the sensitivity of production costs to biomass feedstock costs are evaluated in this study. (C) 2012 Elsevier B.V. All rights reserved.