Evaluation of Multi-Crop Biofuel Pellet Properties and the Life Cycle Assessment

Abstract

Although wood biomass is mostly used to produce solid biofuel pellets, it is important to evaluate the possibilities of using other types of biomass as well. It is not only important to obtain biofuel pellets of suitable quality but also to ensure a sustainable process of producing and using these pellets for energy production. This paper presents an evaluation of the quality characteristics of seven different biofuel pellets made from multi-crop plants (fibrous hemp, maize, and faba bean) and a life cycle assessment (LCA) of the heat production by burning these pellets. The physical-mechanical properties and elemental composition of the pellets are determined according to international standards, as indicated in the methodology section. The LCA was performed using the SimaPro 9.5 software. The complete life cycle from cradle-to-grave is assessed, i.e., from growing plants to spreading ash obtained from pellet burning. An analysis showed that in most cases the produced pellets met the requirements of the standard ISO 17225-6:2021. The lowest negative environmental impact associated with the production of 1 GJ of thermal energy was for pellets made from fibrous hemp and maize biomass (MIX2-1) and pellets made from fibrous hemp and faba bean biomass (MIX2-3). Production of pellets from maize biomass (S-Mz) was found to have the highest carbon footprint (29.1 CO2eq GJ−1) and was associated with the lowest crop yield compared to the other six scenarios.