Hydrogen production, storage and transport for renewable energy and chemicals: An environmental footprint assessment

Abstract

Hydrogen applications range from an energy carrier to a feedstock producing bulk and other chemicals and as an essential reactant in various industrial applications. However, the sustainability of hydrogen production, storage and transport are neither unquestionable nor equal. Hydrogen is produced from natural gas, biogas, aluminium, acid gas, biomass, electrolytic water splitting and others; a total of eleven sources were investigated in this work. The environmental impact of hydrogen production, storage and transport is evaluated in terms of greenhouse gas and energy footprints, acidification, eutrophication, human toxicity potential, and eco-cost. Different electricity mixes and energy footprint accounting approaches, supported by sensitivity analysis, are conducted for a comprehensive overview. H2 produced from acid gas is identified as the production route with the highest eco-benefit (−41,188 €/t H2), while the biomass gasification method incurred the highest eco-cost (11,259 €/t H2). The water electrolysis method shows a net positive energy footprint (60.32 GJ/t H2), suggesting that more energy is used than produced. Considering the operating footprint of storage, and transportation, gaseous hydrogen transported via a pipeline is a better alternative from an environmental point of view, and with a lower energy footprint (38 %–85%) than the other options. Storage and transport (without construction) could have accounted for around 35.5% of the total GHG footprint of a hydrogen value chain (production, storage, transportation and losses) if liquefied and transported via road transport instead of a pipeline. The identified results propose which technologies are less burdensome to the environment.