Early 2008, the European Commission published a proposal on renewable energy that included a biofuel target for 2020 and a methodology with which the sustainability of biofuels can be monitored - including a calculation methodology for determining net GHG emissions. Greenpeace requested CE Delft to draft a report that analyses the GHG methodology proposed by the EC and proposes potential improvements. We conclude that the GHG emission calculation methodology as proposed is more the start of the development of a methodology than a mature methodology. • Default values required for application as a tool are lacking; • Calculation methodologies for important GHG emission contributions such as N2O emissions and soil organic carbon stock changes are not specified; • Indirect land use change and several other items included in IPCC methodology are lacking in the EU proposal. We furthermore conclude that a generic and relatively simple GHG emission calculation tool will probably always be too crude an instrument to produce a reasonably accurate estimation of GHG emissions. Alternative policy options ensuring GHG emissions are not underestimated could be: • A ‘no regret’ short list with respect to cultivation site, utilizable crops, cultivation practice, conversion technology, etc. • A GHG calculation tool with a conservative approach to include intricately determinable emissions, such as indirect land use change.