Sustainable Business Assessment of Remanufacturing Waste Cooking Oil to Produce Biodiesel

Abstract

To replace fossil diesel, biodiesel is produced by the transesterification of vegetable oils. To improve the environmental sustainability, biodiesel can be produced using waste cooking oil (WCO). To highlight to broad relevance of this process, we analyzed the sustainability of WCO-derived biodiesel based on commercial industrial-scale machinery and compared representative plant designs with biodiesel productivities of 5–30 t/day. The technical feasibility was analyzed in terms of productivity, operating costs, power consumption, land footprint, machine delivery cost, number of workers, and diesel consumption. The economic sustainability was evaluated in terms of the cost-to-profit ratio, cost and profit per ton of biodiesel, and daily profit. The environmental sustainability was quantified in terms of the amounts of WCO and produced biodiesel and the energy and CO₂ emissions avoided by remanufacturing. The social sustainability (potential for human development) was analyzed in terms of the number of workers and labor costs. The required remanufacturing technology is considered sufficiently mature and the proposed process minimizes the amount of WCO sent to landfill and avoids the use of new resources for producing diesel, thereby satisfying technical and environmental sustainability requirements, respectively. Although remanufactured biodiesel is more expensive to produce than diesel, a profit range of 3423–27,525 USD/day is achievable. Significant CO₂ emissions can be prevented by remanufacturing WCO, for example, 7–23.1 Mt/year in China and 7.1–23.2 Mt/year in India. High technical, environmental, economic, and social feasibility indexes of 0.99, 0.92, 0.98, and 0.99, respectively, were calculated, giving a high overall sustainability index (SI) of 0.98, highlighting the broad sustainability of the evaluated process. To improve the applicability of the results, the analysis method could be replicated using local metrics to tailor the conclusions to suit the specific requirements of a certain city or country, considering the additional limitations of local taxes, regulations, and incentives.