Greenhouse gas emissions and energy balance of sunflower biodiesel: Identification of its key factors in the supply chain

The production of first generation biofuels, such as sunflower-based biodiesel, is potentially an option for diversifying the energy matrix in several South American countries. However, biofuels present environmental challenges, especially concerning the reduction of greenhouse gas (GHG) emissions. This study, using a life-cycle approach, evaluates the GHG emissions and energy balance of the future nationwide production of sunflower-based biodiesel in Chile. Direct land use change is included in the analysis. The overall findings indicate that sunflower biodiesel, under the most likely production conditions, will have better environmental performance than fossil diesel in terms of both indicators. The agricultural stage is associated to key factors such as land use change, and nitrogen fertilizers. These factors contribute significantly to GHG emissions or energy demand in the biodiesel life cycle. The sensitivity analysis shows that no GHG emission saving could occur if nitrogen fertilizers rate exceeds 330 kg N/ha. In order to reduce the environmental impacts of this biofuel, improvement measures are suggested.

► Potential sunflower biodiesel production in Chile has better GHG balance than diesel. ► Sunflower biodiesel could present an energy saving of 56% compared to diesel. ► N2O field emissions and direct LUC are key factors in the GHG balance of biodiesel. ► For energy demand, nitrogen fertilizers and the use of methanol are key factors. ► Local data are integrated into international database; making LCA more site-specific.