Life cycle sustainability assessment of biodiesel production from waste cooking oil

Waste cooking oil (WCO) biodiesel offers a promising fossil diesel alternative, potentially addressing energy security and pollution mitigation. However, its production faces significant environmental, economic and social challenges due to inherent cross-dimensional trade-offs. To bridge this gap, this study adopts a comprehensive Life Cycle Sustainability Assessment (LCSA) framework to quantify cross-dimensional trade-offs . Environmentally, solid waste accounted for 47.0% of the impact in the human carcinogenic toxicity category and over 90% of freshwater ecotoxicity, marine ecotoxicity and human non-carcinogenic toxicity. Economically, steam consumption in the pretreatment stage accounted for 48.5% of total production costs , followed by steam used in transesterification (19.6%) and potassium hydroxide (19.3%). Socially, the process demonstrates positive performance, particularly through contributions to economic development (26.7% of the total score) and safe and healthy living conditions (10.3%), highlighting the benefits of waste-to-energy conversion. Cross-dimensional analysis identified specific leverage points: solid waste management (environmental) , WCO supply chain governance(social) and steam usage (economic). Sensitivity analysis confirmed steam and KOH usage as critical factors, while scenario modeling demonstrated substituting thermal energy with wind power could reduce environmental impacts and social risks. These findings reveal that achieving sustainability requires negotiating dimensional conflicts rather than pursuing single-criterion maximization.