As a future biofuel production route, Biofuel BV is currently developing a hydrothermal upgrading (HTU) process in which wet biomass is converted at high temperature and pressure to yield biocrude from which to make transport fuels The process provides a means of processing wet organic residues, which are presently of little economic value. CE was asked by Biofuel BV to assess the sustainability of this process. Calculations show that if process development and market introduction proceed as currently projected by Biofuel, an annual reduction of about 2.5-4.5 Mt CO2 can be achieved by 2020 using this technology. Subsequent expansion of production capacity would probably ultimately lead to an annual reduction of 15-30 Mt CO2 by 2040. Introduction of the process would enable further optimisation of waste processing and biomass residue disposal, with actual processing having only limited ecological impact. As there are no land use requirements, neither will there be any impact on diversity or competition with food crops. In socio-economic terms, the HTU process in principle has the advantage of enabling countries with no domestic oil reserves to produce vehicle fuels from waste streams at relatively low cost.