Systematic review of the life cycle optimization literature, and recommendations for performance of life cycle optimization studies

Life cycle optimization (LCO) refers to the integration of objectives calculated using a life-cycle based framework into mathematical optimization problems. Application of LCO may allow for substantial sustainability improvements in many industrial sectors, and provide valuable decision support towards achieving the UN Sustainable Development Goals. This study performed a PRISMA systematic review of LCO literature published between 2012 and 2023 with the goal of developing general guidelines for performance of LCO studies. Three hundred and one sources were reviewed to determine the industrial sector of the modeled system, the life cycle assessment framework used, how objective functions were defined, if uncertainty was included, and the optimization framework used. Results indicate a shift towards evolutionary-based optimization methods relative to previous reviews of the literature. Economic and environmental objective functions were most commonly assessed, while some studies have begun incorporating social objectives into their optimization. Based on the collected data, additional discussion was included related to choice of optimization framework, and definition of objective functions. The collected data and these additional discussions were used to develop a decision tree to aid practitioners in making methodological choices when performing LCO studies. This decision tree will help practitioners manage the trade-offs between the accuracy and efficiency of optimization methods based on the goals of their particular LCO study, and support increased uptake of LCO methodologies across industrial sectors. Increased uptake may provide significant value to researchers and policy makers by enabling investigation of potential sustainability improvement measures where all metrics are simultaneously optimized.