Strategies for life cycle impact reduction of green hydrogen production – Influence of electrolyser value chain design

Green Hydrogen (H2 via renewable-driven electrolysis) is emerging as a vector to meet net-zero emission targets, provided it is produced with a low life cycle impact. While certification schemes for green H2 have been introduced, they mainly focus on the embodied emissions from energy supply during electrolyser operation. This narrow focus on just operation is an oversight, considering that a complete green H2 value chain also includes the electrolyser's manufacturing, transport/installation, and end-of-life. Each step of this chain involves materials and energy flows that impart impacts that undermine the clean and sustainable status of H2. Therefore, holistic and harmonised assessments of the green H2 production chain are required to ensure both economic and environmental deployment of H2. Herein, we conduct an overarching environmental assessment encompassing the production chain described above, using Australia as a case study. Our results indicate that while the energy source has the most impact, material and manufacturing inputs associated with electrolyser production are increasingly significant as the scale of H2 output expands. Moreover, wind power electrolysis has a greater chance of achieving green H2 certification compared to solar powered, while increasing the amount of localised manufactured content and investment in end-of-life recycling of electrolyser components can reduce the overall life cycle impact of green H2 production by 20%.