Life cycle assessment in energy-intensive industries: Cement, steel, glass, plastic

The cement, steel, glass, and plastics sectors are at the forefront of industrial decarbonization and must make effective, evidence-based strategic choices. For the first time, this work analyzes current implementation of life cycle assessment (LCA) methodology, as a key decision lever, across the aforementioned sectors through a critical, systematic literature review of 256 studies. Results reveal differences in how LCA studies are conducted, and that implementation is fragmented. Many studies did not consider functionality when defining a functional unit, and most do not objectively assess data quality. Significant differences also exist regarding the definition of scope and selection of impact categories and interpretations. Therefore, this work provides recommendations for ‘best practice’ in LCA applied to global industrial sectors, aiding in the development of a consistent and transparent approach to cross-sector LCA implementation. Specifically, functional unit types must be properly defined, cross-sector allocation procedures should be intrinsically linked, a ‘cradle-to-cradle’ system boundary should be used where possible, and these aspects should be synergistically implemented across sectors where possible. Data quality should be assessed objectively, with greater uniformity in impact assessment methodologies, impact assessment categories, and reporting methods. Sensitivity and uncertainty assessments should be completed and reported in line with International Standard Organization (ISO) 14040 and 14044, and a greater focus should be placed on future production processes and technology. This will improve LCA applications and outcomes, allow effective cross-sector comparison, and enhance decision making towards net zero.