Biofuels currently appear to be one of the major controversies in the agriculture/environment nexus, not unlike genetically modified organisms. While some countries (such as Brazil) have for quite some time supported successful large-scale programmes to improve the production and consumption of biofuels, policy-makers and research institutions in most developed and developing countries have only recently turned their attention to biofuels. Threat of climate change, new markets for agricultural output, reduced dependencies on OPEC countries and high fossil fuel prices are driving this development. But opposition to biofuels is growing, pointing at the various vulnerabilities - not in the least for developing countries - that come along with large-scale `energy' plantations. Against this background this article analyses the sustainability and vulnerability of biofuels, from the perspective of a sociology of networks and flows. Current biofuel developments should be understood in terms of the emergence of a global integrated biofuel network, where environmental sustainabilities are more easily accommodated than vulnerabilities for marginal and peripheral groups and countries, irrespective of what policy-makers and biofuel advocates tell us.