Assessing the decarbonisation potential of waste-to-hydrogen routes in the energy transition phase: an environmental analytical model

Hydrogen (H2) plays a crucial role in current climate change and energy crisis challenges due to its versatility and low environmental impact, leading to a projected growth in its demand. However, meeting this demand while reducing environmental impact requires innovative solutions, which can support the current energy transition phase and the subsequent large-scale implementation of the electrolysis (El) process. Waste-to-H2 (WtH2) routes, which use waste as a feedstock for H2 production, seem to be valuable for this purpose. To this concern, an environmental analytical model was developed in this work to evaluate the decarbonisation potential offered by three WtH2 routes in the context of the European energy transition. The environmental performance of a Waste-to-Energy plant coupled with an electrolyser, an MSW gasification plant with a syngas treatment unit (Gas-H2) and a Steam Biogas Reforming (SBR) process were therefore compared to that of the most widespread fossil-based H2 production route and the most environmentally promising one, i.e., Steam Methane Reforming and El, respectively. A sensitivity analysis was conducted to assess their environmental performance depending on the state of progress of the energy transition, and the results obtained were then applied in two scenarios, corresponding to the early (i.e., 2020 scenario) and advanced (i.e., 2030 scenario) stages of the European energy transition. The obtained results showed that the SBR offers negative total emissions in many contexts, that the Gas-H2 route is a valuable alternative to fossil-based H2 production, and that the El route is very favourable in contexts where energy is mainly produced from renewable sources. Moreover, it was observed that, especially at an early stage of the energy transition (i.e., 2020 scenario), the use of WtH2 routes could have significantly supported the production of low-carbon H2 and savings in terms of carbon emissions right acquisition. Although, as expected, H2 production from El will become the better alternative from an environmental perspective at an advanced stage of the energy transition process (i.e., 2030 scenario), WtH2 technologies will continue to be able to support the decarbonisation of H2 production.