Biofuels are being developed in the context of three broad economic and policy drivers: reducing greenhouse gas emissions, increasing energy security, and supporting agriculture. Projections of the land and feedstock potentially available for bioenergy indicate that bioenergy development could be resource limited, and food crops may be partially displaced by biofuel feedstocks. One motivation for biofuel development is to reduce greenhouse gas emissions, yet bioelectricity typically provides greater greenhouse gas reductions than biofuel. Moreover, carbon prices affect electricity prices more than petroleum prices. Biofuel development can reduce petroleum supply risks, and the relative balance of policy emphasis on climate change and petroleum security will shape the policies for biofuel development. (C) 2009 The Institution of Chemical Engineers. Published by Elsevier B.V All rights reserved.