Among the existing environmental assessments of bioethanol, the studies suggesting an environmental benefit of bioethanol all ignore the constraints on the availability of biomass resources and the implications competition for biomass has on the assessment. We show that toward 2030, regardless of whether a global or European perspective is applied, the amount of biomass, which can become available for bioethanol or other energy uses, will be physically and economically constrained. This implies that use of biomass or land for bioethanol production will most likely happen at the expense of alternative uses. In this perspective, we show that for the case of a new advanced bioethanol technology, in terms of reducing greenhouse emissions and fossil fuel dependency, more is lost than gained when prioritizing biomass or land for bioethanol. Technology pathways involving heat and power production and/or biogas, natural gas or electricity for transport are advantageous.