Abstract

Purpose This study aims to assess environmentally three different alternatives related to the valorization of Dichrostachys cinerea tree (an invasive plant) as a feedstock for cogeneration facilities installed in the sugarcane industry in Cuba. Methods The Life Cycle Assessment (LCA) methodology was applied to three cogeneration alternatives: (A-1) Electricity generation using raw Dichrostachys cinerea (marabou) as fuel in a back-pressure steam turbine cycle, (A-2) Electricity generation using torrefied marabou as fuel in a back-pressure steam turbine cycle, and (A-3) Electricity generation using torrefied marabou as fuel in an extraction-condensing turbines cycle. The SimaPro software was used for the inventory modeling and the ReCiPe method (midpoint and endpoint approach) was applied to estimate the environmental impacts associated with each case. Results and Discussion The LCA results showed that the electricity generation from torrefied marabou using extractioncondensing turbines (A-3) reduces the environmental impacts as compared with A-1 and A-2. This performance is explained by a lower marabou relative consumption (1.85 kg marabou/kWh generated), which leads to lower emissions associated with harvesting, transportation, and pre-processing stages. Fine Particulate Matter Formation, Terrestrial Acidification, and Water Consumption accounted the worst performance for all the scenarios. Marine Ecotoxicity was the impact category with better environmental performance due to the substitution of synthetic mineral fertilizers by the ashes produced during combustion. The Human health damage category reached the higher impacts on the torrefaction subsystem in the A-3 scenario, representing over 94% of the total environmental burden of the process, causing injuries in respiratory systems. The highest beneficial impact of the cogeneration stage was associated with the consideration of residual steam as an avoided product. Conclusions The use of torrefied marabou in extraction-condensing steam turbines can be considered as an environmentalfriendly technology in the Cuban context. [GRAPHICS] .