Life cycle assessment for the determination of the environmental impacts of an advanced large-scale hydrogen storage system from HyCARE EU project

Abstract

The urgency to reduce carbon emissions and combat climate change has accelerated the development of renewable energies. Hydrogen can be considered an effective vector for the storage of renewable energies but it still faces challenges for the storage at the solid state in large scale systems. The HyCARE European project proposed the development of a prototype at the solid-state using TiFe0.85Mn0.05 alloy as H₂ carrier. The prototype also presents an innovative thermal energy storage system using phase change material (PCM) that is integrated with the metal hydride tanks. This study evaluates the environmental impacts of prototype's construction, use and End-of-Life (EOL) and propose possible solutions to reduce the environmental impacts. A life cycle assessment (LCA) was performed using a functional unit of storing 46 kg of hydrogen over 50 years. To evaluate the system's environmental impacts, different comparisons were done: i) the Hycare integrated system; ii) the system without the integration of the PCM; iii) a simple reference system for storing gaseous H₂ in tubes. The assessment of the HyCARE system identified the metal hydrides powders, particularly titanium, as primary contributors of the system environmental impacts. Energy necessary to operate the prototype accounts for less than 7 % in all impacts, except in ‘Resource use (fossil)'. The EOL phase, modelled with recycling and incineration, reduce impacts, primarily in ‘Resource use (minerals and metals)'. The LCA assessment indicates that the storing solution with the lower environmental impacts lies in adopting the HyCARE system without the integration of the PCM.