A comparison of methodologies for estimating displacement emissions from waste, residue, and by-product biofuel feedstocks

While public awareness of indirect land-use change emissions from using food commodities for biofuels has grown over recent years, the indirect climate impacts of advanced biofuels made from by-products, wastes, and residues are less well understood. While there is a general expectation that such advanced fuels are likely to have lower climate impacts than most purpose-grown feedstocks, many of these materials are “displaced” from their existing uses and may necessitate substitution—often with some kind of climate impact. The indirect emissions attributable to these fuels have been difficult to assess and incorporate into policymaking. This working paper presents a variety of methodological considerations for developing a displacement analysis and illustrates the impacts of the assumptions and decisions on the final results. While there is no one best way to evaluate displacement emissions, they nevertheless warrant some consideration in biofuels policy.