Environmental impacts of torrefied Dichrostachys cinerea cogeneration in a Cuban sugarcane mill: a life cycle assessment approach with a sensitivity analysis

The current study evaluates the environmental impacts of electricity cogeneration from torrefied Dichrostachys cinerea (marabou) in a Cuban sugarcane industry, including electricity transmission and distribution (ET&D) through a Life Cycle Assessment (LCA) methodology. Four stages were studied as most representative of marabou cogeneration (management and forest exploitation, torrefaction, cogeneration, and ET&D), identifying the most significant impacts. The environmental assessment was carried out employing OpenLCA software. Based on the ReCiPe life cycle impact assessment methodology, six impact categories were considered: fine particulate matter formation, fossil resource scarcity, freshwater ecotoxicity, freshwater eutrophication, global warming, and terrestrial ecotoxicity, represented in four stages. The results indicate that the management and forest exploitation stage was the main contributor in almost all the impact categories (ranging from 43.7 to 97.9% depending on the impact), attributed to diesel consumption and its related emissions in biomass harvesting and transportation. In addition, cable reuse (ET&D stage) was identified as a beneficial contributor (up to 49.6%) to the total impact. According to the sensitivity analysis, a truck-railway hybrid transportation scenario for marabou carriage significantly improves the fuel consumption rate compared to the other scenarios, reaching a reduction of up to 191% of the total environmental loads. Due to the relevance of the used technology on the global environment profile, the 72 possible combinations of the current cogeneration technologies (steam generator and electricity generator) in Cuba were evaluated.