Göran BERNDES Department of Physical Resource Theory, Chalmers University of Technology and Göteborg University, SE-412 96 Göteborg, Sweden. Phone: +46 31 772 3148, Fax: +46 31 772 3150, E-mail: frtgb@fy.chalmers.se
There are major expectations that bioenergy will supply large amounts of CO for the future. In this paper the implications of a large-scale substitution of biomass for fossil fuels are analyzed from a water perspective. The aim is: (i) to estimate how much water that is required to grow biomass and convert it to biofuels or electricity, and (ii) to investigate whether global and regional water resources are sufficient to allow for a large-scale substitution of biomass for fossil fuels in the energy sector. It is found that a large-scale expansion of energy crop production would lead to a large increase in evapotranspiration appropriation for human uses, potentially as large as the present evapotranspiration from global cropland. In some countries this could lead to further enhancement of an already stressed water situation. But there are also countries where such impacts are less likely to occur. One major conclusion for future research is that assessments of bioenergy potentials need to consider restrictions from