Biofuels have been recently the subject of a sustained interest due to the ambitious goals set out in developed, and some developing, countries as they transition to more sustainable and self-sufficient energy models. Thus, EU Directive 2003/30 established certain minimimun shares of biofuels in the transport sector for the member states, viz 2% by 2005 and 5.75% by 2010. More recently, the EU Directive 2009/28/EC imposes a target share of 10% renewables in the transport sector by 2020. Different roadmaps can be envisaged based on the varying contributions from first and second-generation biofuels; the controversial role of biomass imports for biofuel production adds some additional uncertainties. Against this backdrop, this work presents a comprehensive view of the technical potential for first-generation biofuels (biodiesel and bioethanol) from energy crops in Spain, and their prospects in the short and mid terms. The methodology has been implemented in a Geographical Information System. The calculated technical potentials for biodiesel range between 730 and 1830 ktoe year(-1) for land occupations of 10% and 25% of the arable land, respectively. The corresponding bioethanol potentials for the same levels of land occupation are 1228 and 3070 ktoe year-1. The calculated potentials indicate that the Spanish agricultural system would be severely strained if the 2020 target, 4755 ktoe year-1, is to be met with locally-grown biofuel crops. The study further estimates the resulting first-generation biofuel costs, and concludes that incentives are needed for the price to be competitive with that of oil-based fuels, even in a scenario of high oil prices. (C) 2011 Elsevier Ltd. All rights reserved.