Life Cycle Environmental Assessment of a Demonstration-Scale OFMSW Biorefinery Producing Advanced Biofuels

Abstract

Biorefineries that convert the organic fraction of municipal solid waste (OFMSW) into advanced biofuels can integrate waste management with renewable energy production. However, their environmental performance remains insufficiently characterised owing to a scarcity of life cycle assessment (LCA) studies based on real operational data. This study presents a gate-to-gate LCA of a demonstration biorefinery processing source-separated food waste into bio-oils, bioethanol, and biogas. The ReCiPe 2016 Midpoint (H) method was applied across 18 impact categories, with system expansion crediting the displacement of rapeseed oil, maize-derived ethanol, and marginal biogas-derived electricity. The net global warming potential (GWP) was 68.5 kg CO2 eq per tonne of wet OFMSW (69% reduction from gross), placing the biorefinery 83–93% below landfilling, 63% below incineration with CHP, and above standalone anaerobic digestion systems that lack the energy-intensive drying and enzymatic hydrolysis steps of the present configuration. Bio-oil and bioethanol achieved net-negative GWP per kilogram of product (−0.89 and −0.66 kg CO2 eq, respectively), whilst eleven of eighteen categories achieved net savings under system expansion. Enzyme production dominated the bioethanol environmental profile (37–94% across categories), whilst drying dominated bio-oil (46–93%). Monte Carlo simulation confirmed that the sign of the net impact stayed unchanged across the entire 95% confidence interval (the interval did not span zero) for 17 of 18 categories.