## 3 Results and Discussion  
### LCA of Hydrogen Production  
#### 3.1.1 Biogas Reforming  
Figure 5 illustrates the environmental impacts of producing 1 kg of hydrogen (H\({}_{2}\)) via biogas reforming across key categories. The anaerobic digestion (AD) plant, air, and electricity consumption are the primary contributors to global warming potential (GWP), accounting for approximately 95% of the total emissions (5.0471 kg CO\({}_{2}\)-eq/kg H\({}_{2}\)). This aligns with the energy-intensive nature of biogas reforming, driven by methane combustion and grid electricity reliance. The impacts on ozone depletion and ionizing radiation are predominantly influenced by electricity consumption, which aligns with previous research indicating that electricity derived from non-renewable sources significantly affects these categories. The AD plant and iron components also contribute significantly to the impacts on terrestrial ecosystems and human health. Material inputs, such as iron, nickel, and concrete, also play significant roles, contributing 18% to terrestrial ecotoxicity (33.44 kg 1,4-DCB eq) and 22% to mineral resource scarcity (0.1168 kg Cu eq). Freshwater eutrophication (0.0120 kg SO\({}_{2}\) eq) and fine particulate matter formation (0.0243 kg PM2.5 eq) are primarily associated with AD plant operations. Water consumption remains relatively low (0.0485 m\({}^{3}\)/kg H\({}_{2}\)), mainly due to cooling, reforming reactions, and gas purification processes. The negative environmental effects of constructing and demolishing a biogas reforming and gasification facility are relatively insignificant. Operating the plant at a high capacity can further reduce environmental impacts. The evidence indicates that long-lived biogas plants have minimal environmental impact during construction and demolition. During plant operation, CH\({}_{4}\) emissions from overpressure valves or leaks can significantly contribute to GHG emissions. Construction and demolition of the installations have minimal environmental impacts [21].  
Figure 5: Environmental impacts of 1 kg of H\({}_{2}\) production from biogas reforming.  
The dominance of AD plant operations and electricity in global warming potential (GWP) corroborates the findings of [PERSON] et al. (2020) [46], who identified biogas combustion and fossil-based energy inputs as critical emission sources. However, biogas reforming still exhibits a 40-60% lower GWP than steam methane reforming (SMR) due to renewable feedstock utilization ([PERSON] et al., 2016) [11]. The high ozone depletion and ionizing radiation impacts (0.3729 kBq Co-60 eq) reflect reliance on non-renewable electricity, consistent with [PERSON] et al. (2019) [47], who emphasized grid dependency as a key drawback. Particulate emissions from biomass handling and iron components align with [PERSON] et al. (2017) [48], who linked these to mechanical processing and catalyst use. Ecotoxicity from nickel and concrete mirrors [PERSON] and [PERSON] (2001) [49], who attributed heavy metal leaching to infrastructure and reforming catalysts. Despite lower land use (0.0358 m\({}^{2}\) a crop eq) compared to electrolysis [50], optimizing renewable energy integration and material efficiency remains critical to mitigate trade-offs.