Renewable hydrogen imports for the German energy transition – A comparative life cycle assessment

Abstract

Hydrogen imports are considered as a promising pillar for the defossilisation of the German energy system. One of the main concerns when discussing hydrogen solutions is its environmental performance, especially with regard to its greenhouse gas emissions. While a large number of life cycle assessments (LCA) helps to thoroughly understand the impacts of domestic hydrogen production, the assessment of international supply chains remains scarce. On that account, this study performs a comparative LCA of liquefied hydrogen imports from Chile, Canada and Morocco to Germany in a cradle-to-gate approach. A scenario and sensitivity analysis allows to analyse the main drivers on the ecological meaningfulness and to derive recommendations for the establishment of renewable hydrogen supply chains. The results show that the import of renewable hydrogen can outperform domestic production in some cases. In the defined base case, the global warming potential of hydrogen delivered to the German gas grid ranges from 1.505 to 2.457 kgCO2eq/kgH2 or 45.2 to 73.7 gCO2eq/kWhH2,LHV for wind-based imports. Domestically produced hydrogen from wind shows emissions of 1.989 kgCO2eq/kgH2 or 59.7 gCO2eq/kWhH2,LHV. Results for hydrogen produced by solar PV range from 3.787 to 4.008 kgCO2eq/kgH2 or 113.6 to 120.3 gCO2eq/kWhH2,LHV for imports (5.195 kgCO2eq/kgH2 or 155.9 gCO2eq/kWhH2,LHV for domestic production). However, while for domestic hydrogen electrolysis is by far the predominant process step, the entire process chain needs to be taken into consideration for importing cases (e.g. the shipping distance and fuel, the electricity source for hydrogen liquefaction).