The future exploitation of global energy resources is currently being hotly debated by politicians and by sections of the scientific community but there is little guidance available in the engineering literature as to the full gamut of options or their viability with respect to fuelling the world's vehicles. In the automotive industry extensive research is being undertaken on the use of alternative fuels in internal combustion engines and on the development of alternative powerplants but often the long-term strategy and sustainability of the energy sources to produce these fuels is not clearly enunciated. The requirement to reduce CO2 emissions in the face of accelerating global warming scenarios and the depletion of fossil-fuel resources has led to the widespread assumption that some form of 'hydrogen economy' will prevail; this view is seldom justified or challenged. As oil and natural gas resources begin to deplete it is vital to consider how to exploit the remaining reserves more efficiently and how best to produce, distribute and utilise the fuel which may form the basis of the future energy economy. The paper discusses the origins of our dependency on fossil fuels and looks at issues related to the depletion of their resources and their effects on the global climate. Two possible long-term energy strategies are considered and the impact of these on the direction of future automotive fuels is considered. The issues involved with the provision of infrastructure for fuel distribution are assessed and the compatibility of this infrastructure with that required for fuelling future generation vehicles, including those powered by fuel-cells is discussed. The exploitation and limitations of biomass fuels are considered, in particular the use of alcohol-based fuels in internal combustion engines and their compatibility with future trends in engine technology to improve fuel economy are discussed. Copyright © 2007 SAE International.