LCA comparison analysis for two types of H-2 carriers: Methanol and ammonia

This paper presents a comparative life cycle assessment of two types of H-2 carriers, methanol and ammonia, using GaBi 10 software. Two types of H-2 carriers that is, methanol and ammonia are compared from coal, natural gas and renewables, respectively. The full supply chain is considered in the carbon footprint evaluation, which contains production, storage, transportation, and utilization phase. The energy analysis results show that H-2 carrier produced from natural gas has higher energy efficiency than that from renewables, which can be attributed to the high energy consumption during H-2 generation in the latter. Carbon footprint evaluation indicates that solar PV-based ammonia production route has the lowest GWP in all scenarios, with a value of 43.9 g of CO2-Equation MJ(-1) of ammonia. In addition, electricity has been found as the key factor affecting GHG emissions in the routes of fuels produced from renewable H-2 through sensitivity analysis. By optimizing electricity generation and expanding the carbon capture scale of power plant, the GHG emissions level of CCU-based methanol production route and solar PV-based ammonia production route can be further reduced.