Converting waste cooking oil to biodiesel in China: Environmental impacts and economic feasibility

Abstract The sustainability of producing biodiesel from waste cooking oil (WCO) needs to be thoroughly examined since it is a promising multiple-advantage solution to strengthening energy security, promoting a circular economy, minimizing waste and environmental pollution, and safeguarding food safety. In this study, we employed life cycle assessment (LCA) and life cycle cost (LCC) modeling to evaluate the environmental impacts and economic competitiveness of biodiesel production from WCO in China. The endpoint impacts, including the damage to human health, ecosystem quality, and resource availability, and relevant midpoint impacts were examined. The results show that compared to conventional fossil diesel, the overall endpoint environmental impacts of WCO-based biodiesel are lower, particularly in terms of resource depletion. However, for the midpoint impacts, WCO-based biodiesel has higher impacts on climate change, particulate matter generation, photochemical oxidant formation, human toxicity, and water depletion. The majority of the environmental impacts are due to transesterification, except for water depletion, which is mainly derived from the transportation of the biodiesel fuel. The LCC of the biodiesel is estimated to be 6460 RMB per ton, which is about 31% higher than that of fossil diesel (4921 RMB per ton). The LCC of WCO-based biodiesel is mainly determined by the WCO collection, with a share of 83%. The high purchasing price of WCO feedstock and the fluctuations in international oil prices lead to difficulties in biodiesel industry development. Additionally, the multiple consumers of WCO, the low energy conversion rate, and the immature utilization of the by-products also hinder the massive deployment of WCO-based biodiesel in China.