Technological variation and the US renewable fuel standard

The US Renewable Fuel Standard contains a policy bias that undermines the three-broad policy goals of rural development, energy security, and greenhouse gas reductions. This policy bias, wherein a narrow range of options is expected to address broad societal objectives, contributes to a persistence of first-generation biofuels and limits technical variation. Renewable fuel content requirements have helped to expand the use of ethanol and biodiesel in the short term. However, long-term changes will require greater technological variation to stimulate innovation for the development of sustainable renewable fuel pathways.