Carbon footprint analysis of biohydrogen derived from urban solid waste in southeastern Brazilian

Hydrogen plays a fundamental role in the context of decarbonization as a pillar of energy transition. It can be produced through different manners, including from residual biomass. Aiming to mitigate the effects of climate change, this study seeks to estimate Greenhouse Gas (GHG) emissions, specifically the carbon footprint of biohydrogen (Bio-H2) 2 ) derived from dark fermentation of Organic Fractions of Urban Solid Waste (OFUSW) and reforming biomethane from Landfill Gas (LFG) at landfill consortia. The goal of this study is to address the question of how Low Carbon Emission Hydrogen generation may be achieved. Population and solid waste generation projections for the next 20 years at landfill consortia in the Brazilian southeast were estimated. The potential for generating (Bio-H2) 2 ) and Life Cycle Analysis (LCA) were defined according to ABNT ISO 14040 and ABNT ISO 14044 using the two aforementioned scenarios. The results showed that the bio-H2 2 potential generation from methane flows were 654, 517, 453, and 162 million m3, 3 , respectively for the states of Sao o Paulo, Minas Gerais, Rio de Janeiro, and Espirito Santo. Moreover, the carbon footprint calculations for bio-H2 2 generation showed that up to 9.23 and 18.41 gCO2eq/MJ, 2eq /MJ, respectively, are generated by producing 1.0 MJ of hydrogen via dark fermentation and the biogas reforming process. These values indicated a reduction of up to 75% for biogas reformation, and 87% for dark fermentation, compared to conventional hydrogen production from natural gas. This underscores the significance of waste energy recovery management aiming to achieve the goal of producing Low Carbon Emission Hydrogen.