This paper examines the potential roles of Fischer-Tropsch (FT) synfuels in the 21st century with a global energy model treating the entire fuel supply chain in detail. The major conclusions are the following. First. FT synfuels become a major alternative fuel regardless Of CO2 policy due to their low transportation costs and compatibility with existing petroleum infrastructure and vehicles. Secondly, the FT process brings stranded gas to world markets until around 2050. In a 550 ppm CO2 stabilization case thereafter, producing FT synfuels from biomass, whose competitiveness is robust against its capital costs, and their interregional trade enable a worldwide diffusion of carbon-neutral fuels. This provides a significant source of income for developing regions, such as Latin America and Sub-Saharan Africa. Thirdly, FT synfuels play a crucial role in meeting the growing transportation energy demand and assuring diversified supplies of transportation fuels. Increasing portions of FT liquids are refined to FT-kerosene to be provided for the rapidly growing aviation sector in the second half of the century. Furthermore, upgrading FT-naphtha into FT-gasoline proves to be critically important. FT synfuels' participation could help the development in Africa through technological contributions of the South African leading companies in the world synfuel industry. (C) 2008 Elsevier Ltd. All rights reserved.