This study provides a review of the emergence of hydrogen within low-carbon pathways from different integrated energy system models. The objective is to understand the drivers and policy scenarios that lead to the emergence of hydrogen over other low-carbon technologies. The review is divided into global, multi-regional and national integrated energy system models with drivers, marginal abatement costs and timing of hydrogen emergence assessed. Hydrogen's use in energy systems is complex as a result of its relationship with other energy sources. It was found that bioenergy can act as both a competitor and driver for hydrogen energy, along with increased electrification and high renewable electricity scenarios. However, electric vehicles are a main competitor in the passenger vehicle sector. In reviewed results, hydrogen mainly emerges after 2030; although, some technologies emerge as early as 2020 and as late as 2050. The uncertainty and complexity surrounding hydrogen may be as a result of the difficulty of representing hydrogen technologies and systems in energy system models. This study can allow policy makers to assess the various options to be considered regarding hydrogen and make informed decisions for moving towards a decarbonised energy system.