Micro-algae have received considerable interest as a potential feedstock for producing
sustainable transport fuels (biofuels). The perceived benefits provide the underpinning
rationale for much of the public support directed towards micro-algae research. Here we
examine three aspects of micro-algae production that will ultimately determine the future
economic viability and environmental sustainability: the energy and carbon balance, environmental
impacts and production cost. This analysis combines systematic review and metaanalysis
with insights gained from expert workshops.