Long-term decarbonisation of hard-to-abate industrial thermal demand for 100 % renewable energy systems

Decarbonising the hard-to-abate sectors, such as industry, is a complex challenge towards carbon-neutral energy systems. Solutions and technologies for industry decarbonisation must be embedded into an energy model while optimising the transition pathways of the whole energy system to fully grasp the complex synergies between all sectors. This study proposes an enhanced modelling approach based on the H2RES long-term optimisation tool to include industrial heating technologies as endogenous variables, disaggregated by three temperature levels, and applies it to the decarbonisation of Italian industry. Results show that the temperature level of industrial heat demand is a crucial discriminating factor. Heat pumps can directly electrify the low-temperature demand, while biofuels are the most cost-effective solution for medium- and high-temperature demand. Biomass limited availability strongly affects the optimisation results. Indirect electrification plays a key role, since electrofuels cover a share up to 55 % of heat demand, resulting in lower system costs than direct hydrogen combustion. The outcomes show how the best strategies to decarbonise hard-to-abate sectors cannot be identified separately from the entire energy system and without considering temperature constraints and overall resource availability. It is crucial to rely on modelling tools able to describe such issue and interconnections within all energy sectors.