The aim of this study is to analyze the world's future energy supply, in general, and the cost-effective fuel choices in the transportation sector, in particular, under stringent CO2 constraints. The analysis is carried out with the help of a global energy system model GET-R 1.0, developed specifically for this project. It is a linear programming model and it has three end-use sectors: electricity, heat and transportation fuel. It is set up to generate the energy supply mix that would meet exogenously given energy demands at the lowest global cost. We have chosen an upper limit on CO2 emissions corresponding to an atmospheric CO2 concentration target of 400 ppm, by the year 2100. We find that it is cost-effective to carry out the transition from gasoline/diesel in the middle of the century and that hydrogen becomes the most cost-efficient fuel in the long run. Within the electricity production sector all renewable energy sources show a pattern of increasing contributions during the century and solar produced hydrogen will dominate by year 2100. Biomass is the dominant fuel in the heat sector. Further, we compare our results with those generated using a globally aggregated version of the model. We find that the regionalization only marginally affects the general pattern.
