Beyond carbon in socioenvironmental assessment: Life cycle assessment as a decision support tool for net-zero energy systems
Emily Grubert
Abstract
Decarbonizing the energy system is a crucial task for mitigating climate change. Although sustainability assessment methods like life cycle assessment (LCA) are designed for multicriteria sustainability evaluation, greenhouse gas (GHG) emissions tend to dominate recommendations and analyses because of the clear relationship between a simple indicator and the many serious impacts of climate change. When faced with a choice among multiple net-zero GHG infrastructure options, however, GHG emissions are no longer available as an overall proxy for sustainability. The socioenvironmental assessment community thus faces a challenge in robustly evaluating relative sustainability for net-zero GHG energy systems and the systems that use them. Methodological issues like data collection and management, context-specific impact assessment, normalization, and multicriteria prioritization remain underdeveloped in part because they are less important in contexts where GHG emissions are assumed to dominate decisions. Broadly, the ability to robustly and rigorously manage and communicate epistemic uncertainty in true multicriteria sustainability assessment contexts remains underdeveloped in LCA because GHGs have been such a reliably dominant indicator. This piece argues that to survive as a relevant, useful tool in a zero-GHG future, LCA ought to mature as a decision support tool rather than as a pure assessment tool. Methodological attention focused on decision support, including robust approaches to sensitivity and scenario analysis, is particularly needed. Issue areas for LCA “beyond carbon” are categorized by LCA phase, illustrated with examples from carbon capture and storage (CCS) evaluations. Leveraging existing strengths of multicriteria sustainability assessment methodologies like LCA, and investing effort in strengthening their value for decision support, could improve long-term sustainability outcomes.