This paper analyses the relationships between the European Commission's legal and political instruments and the changing spatialities of European Union (EU) biofuel development. This interlinkage of law, policy and space are examined through the conceptual lens of assemblages. Originally, despite the multiple pathways to produce biofuels presented by the Commission, the topology of EU development became regionally clustered around European agricultural actors. Resulting from the fast growth of biofuels consumption in the EU, these localized assemblages later became connected with international networks of trading crop-based ethanol and biodiesel. Vis-a-vis this growth, topologically fluid consequences such as indirect land-use changes have begun to influence the dynamics of EU biofuel development. Concurrently, the Commission's mode of steering has transformed from strategies and incentives into regulation that is increasingly geared towards instruments of carbon calculation. With these instruments, the Commission has begun to reorient the assemblage from its agricultural roots towards alternatives with lower land-use impacts. However, this paper argues that there is a need to strengthen the steering of biofuels with topologically sensitive instruments in order to cope with the complex dynamics of the localized assemblages of biofuels production.