Life cycle assessment of hydrogen production pathways in Canada

Canada has the potential to produce hydrogen as part of the clean fuel transition of its existing energy sector to a low-carbon economy, commitment that will support reaching net-zero emissions goal by 2050. Domestic hydrogen production is leveraged by the availability of diverse energy sources from fossil fuels to renewable electricity. Canada has the one of the cleanest electricity systems in the world with over 83% of electricity from non-emitting sources. Additionally, production of low-carbon hydrogen has the potential to be internationally traded. However, it is necessary to define and measure the carbon intensities of potential hydrogen production pathways in Canada in order to define low-carbon hydrogen in future standards. It is within this context that the National Research Council Canada (NRC), through its Advanced Clean Energy Program, has undertaken the development of a Life Cycle Assessment of Hydrogen Production Pathways in Canada Study, with support of the Natural Resources Canada (NRCan)’s Office of Energy Research and Development (OERD) and collaborators CanmetENERGY in Devon (CE-D), and CanmetENERGY in Varennes (CE-V) of NRCan, which have joined their efforts and expertise to provide hydrogen production process simulation results to complete the current study. The purpose of this study is to develop a detailed and complete methodology based on a life cycle assessment (LCA) approach to assess different carbon intensities of hydrogen production in order to provide a consistent and verifiable greenhouse gases (GHG) estimation, including definition of system boundaries and building life cycle inventories for a Canadian context. Additionally, this report provides results of performing the proposed LCA-based methodological framework for two hydrogen production pathways in a Canadian context using steam methane reforming with natural gas and without carbon capture and alkaline electrolysis using grid electricity. After performing a scoping review of relevant hydrogen LCA peer-reviewed studies, critical life cycle assessment methodological options were identified for harmonizing LCA of hydrogen production frameworks. Based on current life cycle assessment normative, a methodological framework is developed to quantify carbon intensities of hydrogen production. LCA methodological choices such as definition of functional unit, system boundaries, and life cycle inventory criteria are aligned to relevant and current low-carbon intensity hydrogen standards. The LCA-based methodology is an attributional LCA, with the system boundaries being to the point of hydrogen production (‘well-to-gate’ approach). The life cycle inventory data for the foreground system comes from modelling and simulation results of the processes selected in this study. A life cycle assessment was conducted to the steam methane reforming as baseline pathway and the alkaline electrolysis pathway. Life cycle GHG emissions results show that the baseline hydrogen pathway presents a wide range of improvement in comparison to an estimated low-carbon hydrogen threshold. Electrolysis pathway shows its carbon intensities depend on the share of renewable energy sources used to generate electricity as feedstock in the electrolysis process. Further LCAs for the remaining hydrogen pathways in a Canadian context will be performed and results will be published in a new report. It is important to note that the accuracy and completeness of the life cycle inventory data could be improved with primary data from current industry, hence it is recommended that the LCA results in the present report may be revised with use cases from current hydrogen projects developed in a Canadian context. Additional recommended steps, include start a wide consultation process with stakeholders to revise life cycle GHG emissions estimates and to set the final carbon intensities threshold(s).