Towards industrial decarbonisation: Assessing the potential of hydrogen and electrofuels in hard-to-abate sectors

Decarbonising hard-to-electrify industry is a key challenge for planning 100% renewable energy systems. This work assesses the potential role of hydrogen and electrofuels through an integrated energy system model with industry disaggregated by sub-sector and temperature level, overcoming the aggregated representation of industry typically adopted in system-level studies. Alternative pathways to decarbonise industrial final energy consumption have been considered. A hydrogen-based scenario applies direct hydrogen combustion in boilers and furnaces, converting gas burners into hydrogen burners, and using green hydrogen in direct reduced iron production. Other scenarios exploit existing infrastructure by switching fuel to synthetic natural gas, produced by combining hydrogen and CO2 or by biomass hydrogenation. All the pathways allow industry decarbonisation, leading to different optimal energy system configurations. Across scenarios, electrification of low- and medium-temperature heat via industrial heat pumps is crucial. e-Methane penetration intensifies indirect electrification and introduces a carbon capture requirement, showing the highest decarbonisation costs. Direct hydrogen applications increase system efficiency but require additional costs for hydrogen transport and end-use adaptation. Biomass hydrogenation reduces electricity needs and decarbonisation costs by scaling biomass use, raising feasibility issues linked to sustainable supply chains and biomass price exposure. Carbon abatement costs are extremely sensitive to the fossil fuel price context. Under low fossil price assumptions, they remain relatively high in the range of 125-180€/tCO2, while, under high fossil price assumptions they drop substantially up to slightly negative values. Industry decarbonisation strategies affect the entire system configuration and should be assessed and modelled through an integrated energy system approach.