In sub-Saharan Africa, commercial bioenergy production has been hailed as a new form of ‘green capitalism’ that will deliver ‘win-win’ outcomes and ‘pro poor’ development. Yet in an era of global economic recession and soaring food prices, biofuel ‘sustainability’ has been at the centre of controversy. This paper focuses on the case of post-war Sierra Leone, a country that has over the last decade been consistently ranked as one of the poorest in the world, facing food insecurity, high unemployment and entrenched poverty. Following a recent government strategy to secure foreign direct investment in biofuels production in agriculturally rich regions of the country, the largest foreign investment in Sierra Leone since the end of its civil war has been secured: a Swiss company is to invest US$368 million into a large-scale biofuels project over the course of 3 years, and promises to simultaneously stimulate an enabling environment for investment, provide job opportunities for youth and increase food production. For multiple actors involved in the project, the concept of ‘sustainability’ is crucial but accordingly there are varying interpretations of its meaning. Such differences in interpretation and the complex contradictions within discourses of sustainability are in turn framed by the various scales within which these actors are situated. While attempts have been made to manage these contradictions through global sustainability standards, the unequal power relations between different actors will ultimately determine the ways in which they are likely to be resolved. The paper concludes by reflecting on how these processes may be contributing to a changing governance landscape and wider global political economy within which bioenergy is being produced, processed and consumed.