Chapter 9: Learning from the Life Cycle Assessment of Power-to-hydrogen Systems

In a decarbonisation context, understanding the potential environmental implications of power-to-gas pathways is key. Life cycle assessment (LCA) is widely recognized as a tool of choice to quantify the environmental impacts of a product or service. Here we assess various hydrogen production routes, including steam methane reforming (SMR) and electrolysis. Results show that the environmental footprint of hydrogen production is intricately linked to factors such as the electricity source and methane leakage. While “green” hydrogen widely inherits the properties of its electricity source, the life cycle greenhouse gas emissions of “blue” hydrogen are significantly influenced by the upstream natural gas supply chain. The study underscores the importance of stringent certification for ensuring low-carbon hydrogen production. Comparisons with other sectors, such as transportation, highlight the unique challenges and opportunities posed by hydrogen production methods. Looking ahead, future analyses should prioritize application-level assessments and quantify the environmental profiles of power-to-gas systems amid evolving contexts and changing energy landscapes.