Future-oriented environmental impact of green hydrogen supply chains with underground storage

Abstract

This research presents a forward-looking life cycle analysis of green hydrogen production via an alkaline electrolyser, integrated within a standalone hybrid energy system based on solar photovoltaics and wind power technologies. The system includes underground storage to ensure stable hydrogen supply. Environmental impacts are explored under future decarbonisation pathways for the electricity sector, as projected by the LUT Energy System Transition Model. The analysis leverages the premise framework in combination with the Activity Browser platform. Four geographically and climatically distinct countries, Finland, Germany, Spain, and Chile, are selected as case studies to reflect variations in renewable energy resource profiles. Chile, benefiting from a higher contribution of solar photovoltaics, exhibits the lowest environmental impact, whereas Finland and Germany, with wind power-dominated energy inputs, demonstrate comparatively higher emissions. Over time, the global warming potential (GWP100) associated with hydrogen production (per kWhH2,LHV) declines markedly, from 30.7–47.2 g CO₂-eq in 2020 to 12.0–16.5 g CO₂-eq by 2050. The remaining emissions by mid-century primarily result from the extraction and processing of materials, namely steel, silicon, aluminium, and concrete, as well as the continued use of fossil fuels in freight and marine transport as part of the background system. These outcomes underscore the necessity of refining life cycle data and methodologies. Further emission reductions may be achieved by decarbonising upstream material flows and transport activities through renewable energy integration.