Flaws in the interpretation phase of bioenergy LCA fuel the debate and mislead policymakers

We hypothesize that the current heated scientific debate on bioenergy sustainability is fuelled by flaws in the interpretation phase of bioenergy LCA studies rather than by the lack of studies or shared methodologies. The interpretation phase is the key step in LCA studies, which guarantees their quality and consistency and gives meaning to the work carried out by delivering results that are consistent with the defined goal and scope, which reach conclusions, and explain limitations.

To test our hypothesis, we selected the 100 most cited articles found in Scopus utilizing a query to include most of the relevant works on LCA of bioenergy. The rationale underpinning the choice of the most cited articles is that these are presumably the most influential. A further screening identified off-topic articles, reviews, and methodological papers, which were discarded. We have also checked whether the articles analysed referred to the ISO standards. The study is organized as a reasoned and parametrized review in which we assess the methodological approach of the studies, rather than the results obtained.

We find that overlooking some of the fundamental steps in the interpretation phase in bioenergy LCA is a rather common practice. Although most of the studies referred to the ISO standards, the identification of issues, their framing with sensitivity analyses, and the identification and reporting of limitations, which are all needed to comply with ISO14044 standards, are often neglected by practitioners. The most problematic part of the interpretation phase is the consistency check. In most cases, the assessment framework built is not apt at answering the question set in the goal. Limitations are properly identified and reported only in few studies.

We conclude that in many studies either the conclusions and recommendations drawn are not robust because the inventory and the impact assessment phases are not consistent with the goal of the study, or the conclusions and recommendations go well beyond what the limitations of the study would allow. In our opinion, these flaws in the interpretation phase of influential LCA studies are among the responsible factors that continue to fuel the debate around the sustainability of bioenergy. We report a set of recommendations both for LCA practitioners and for users to guide the LCA practitioners in properly organizing and reporting their work, and to facilitate the readers in understanding and evaluating the significance and applicability of the results presented.