CINEA has published a report to analyse how we can leverage digital transformation into cities towards effective climate action. Digitalization can improve cities' liveability in multiple domains, such as economic development, housing, the management and operation of mobility and energy. In this report, the methodology developed for the literature review of the urban energy systems framework is presented. The role of citizens towards the digitalisation of urban energy systems is also included. Furthermore, replicable digital technologies and tools are reviewed with the related business models that drive the urban energy transition, citizen engagement, and impact on energy sectors. Finally, learning processes and knowledge sharing between experts of digitalisation in urban energy systems is delivered with the outlook for the years 2025, 2030, and 2040, defining the barriers and gaps and setting realistic goals.