Life cycle assessment of electricity generation from combustion and gasification of biomass in Mexico

One measure to mitigate some of the nowadays environmental problems is the generation of products from renewable resources. In this context, this study's objective is to evaluate the environmental impacts associated with the use of sugarcane and agave bagasse from Mexico as a raw material for the generation of bioenergy, applying a life cycle assessment approach. Four scenarios were compared to determine the optimal feedstock (sugarcane or agave) and processing routes (combustion or gasification) from an environmental perspective. Life cycle assessment is performed according to the cradle-to-gate approach. In the case of the two-feedstocks studied, it was observed that the feedstock processing stage has high impact values in almost all impact categories. In this sense, it was observed that the combustion scenarios have high impact values in terms of ozone depletion potential (4.73 × 10⁻⁶ and 7.59 × 10⁻⁷ kg CFC11 eq), terrestrial acidification potential (1.41 × 10⁻² and 7.82 × 10⁻³ kg SO₂ eq), and fossil fuel potential (9.30 × 10⁻² and 0.12 kg oil eq) for sugar extraction and bacanora production, respectively). For the gasification scenarios, the highest impact values ​​were observed for the terrestrial acidification potential (1.27 × 10⁻² kg SO₂ eq) and fossil fuel potential (8.41 × 10⁻² kg oil eq) for sugar production and the ozone depletion potential (6.85 × 10⁻⁷ kg CFC11 eq), human toxicity potential - non-cancer (2.05 × 10⁻² kg1,4-DCB) and fossil fuel potential (0.11kg oil eq) for bacanora production. Furthermore, it was observed that the sugarcane cultivation stage generates between 2 and 6 times more impact than the agave cultivation stage for almost all impact categories. Regarding the stages related to thermochemical processes, the impact values were relatively low, except for the following categories global warming potential, photochemical oxidation formation potential - humans, photochemical oxidation formation potential - ecosystems, terrestrial acidification potential, and water consumption potential, between 21 % and 88 % for the combustion process and between 32 % and 63 % for the gasification process. The main results of the comparisons between the four scenarios showed that the best scenario from an environmental perspective is agave bagasse combustion, followed by agave bagasse gasification, sugarcane bagasse gasification, and sugarcane bagasse combustion.