Prospective carbon footprint comparison of hydrogen options

Abstract

The Life Cycle Assessment methodology is often used to evaluate the environmental performance of hydrogen energy systems. However, even though hydrogen is usually seen as a strategic energy carrier for the future energy sector, there is a lack of case studies assessing its prospective life-cycle performance. In order to contribute to filling this gap, this work addresses a carbon footprint comparison of hydrogen options from a prospective standpoint. Four relevant hydrogen production pathways (steam methane reforming, grid-powered alkaline electrolysis, wind-powered alkaline electrolysis, and biomass gasification) under three time scenarios (reference, year 2030, and year 2050) are assessed, taking into account the expected evolution of key technical parameters such as efficiencies, lifespans, and the grid electricity mix. The results show a favourable carbon footprint of renewable hydrogen from biomass gasification and wind electrolysis, with a relatively steady near-zero carbon footprint. Despite the unfavourable carbon footprint results of conventional hydrogen from steam methane reforming and hydrogen from grid electrolysis, the latter is associated with a rapid trend towards a suitable long-term carbon footprint.