Abstract: The integrated approach used in the REBECa project (2007-2011), which was conducted by a number of now ENVS researchers together with partners from other institutions will be presented. The project departed in the policy targets for renewable energy in the transport sector, and investigated consequences of fulfilling these targets using biofuels produced from Danish crops, and existing - while not only mature - technology. One line in the project investigated the consequences for emission changes, geographical distributions and air quality, another the land use effects of various agricultural strategies. A combined WTW and welfare economic analysis was performed.