Abstract
Many Countries have set extremely ambitious targets to speed up the energy transition and reach zero emission by 2050. This has gained even more important motifs in light of the recent geo-political events and the energy crisis that have been shaking the world balance and messing with the energy agendas of many Countries, especially those with a high reliance on imported fossil fuels. Thus, it has become ever more important to find solutions for the decarbonisation of every economic sector including also the “hard-to-abate” ones. Different solutions have been identified for the decarbonisation of such sectors that for their heterogeneity and specific requirements need sometimes unique technologies. Most proposed solutions entails a tighter connection to the power system either through direct or indirect electrification. This research wants to shade light on the most promising technologies, their impact and potential synergies with the entire energy system thus supporting Sustainable Development Goals 7, 8, 9 and 13. Furthermore, this review also discuss how the decarbonisation of hard-to-abate sectors is analysed in energy system modelling for energy planning purposes, what are the most used approaches and what each of them entails, critically discussing and analysing the main challenges while offering potential solutions to tackle them.