Can the mass utilization of biofuels help reduce greenhouse gas emissions and dependence on fossil fuels? Four particular types of biofuels have been the subject of extensive study in this regard: corn ethanol, sugar cane ethanol, cellulosic ethanol, and biodiesel. This paper overviews the evidence from the literature on Lifecycle Assessment studies pertaining to these four fuels and finds that no definitive answer to these questions exists in the literature. The example of biofuels co-products is used to illustrate the reason why no easy answer can be arrived at from these studies. The deeper sources of variation within the literature are identified as well as the requirements that would be needed to formulate an LCA which can provide conclusive and actionable answers.
A review of the Lifecycle Assessment literature concerning biofuels found no conclusive answers on the important and policy-relevant questions of whether biofuels can help reduce emissions of greenhouse gases, and whether they are an efficient source of energy. This inconclusiveness is attributed to the problematic specification of these papers, which cannot give actionable and policy-relevant answers. The main problems in the specification of the papers are: the reliance on aggregate-based modeling rather than investigating the impact of specific policies, the absence of integration within a dynamic economic model that includes the price effects, the focus on emissions quantities rather than the environmental impact of the emissions, and missing. This paper draws on insights from economics and philosophy of science to explain the underlying reasons why LCA studies fail to reach conclusive answers.