Cradle-to-grave life cycle assessment of Lebanese biomass briquettes

Abstract

The bioenergy sector is showing a recent development in Lebanon, a Mediterranean country, where the valorization of forestry and agricultural waste through briquetting consists one of the mostly applied and targeted applications. This study aims at analyzing the life cycle environmental impacts of biomass briquettes produced from olive pruning residues and used for heating purposes in traditional Lebanese stoves. The biomass briquettes are mainly introduced as a replacement for the light fossil fuels widespread used in similar stoves for the same purpose. Consequently, this paper also extends the literature-found comparison of the consumption phases between biomass briquettes and light fossil fuels to a comparative gate-to-gate LCA of these products. For the briquette itself, the results indicate that the "consumption" life cycle stage is the one that contributes to the most to all damage categories. Its contribution is 61%, 94%, 80% and 79% of the total contribution to "Human Health", "Ecosystem quality", "Climate change", and "Resources" damage categories respectively. When compared to light fossil fuels, biomass briquettes present overall better environmental results with exceptions for "Non-carcinogens" (6.28E-04 kg C2H3Cleq), "Aquatic ecotoxicity" (1.01E-02 kg TEG water), "Terrestrial ecotoxicity" (5.04E-02 kg TEG soil), and "Land occupation" (9.37E-03 m2org.able) impact categories. This overall outcome is mainly linked to the fact that biomass briquettes are used as a replacement to traditionally adopted energy sources while reducing burning activities in the field. Moreover, sensitivity and uncertainty analyses are also conducted to verify the robustness of the results.