The energy system is facing an unprecedented transformation mostly driven by the process of decarbonization making renewable energy sources the new main player. At the same time, the transformation of other sectors is bringing relevant changes also on the load side (e.g. electric vehicles, heat pumps). In this process, digitalization is emerging as a key enabler. It can actually be stated that digitalization is not an option but a necessity. The power system is consequently becoming a large, programmable cyber physical infrastructure with a high level of complexity. The presentation will address this complexity by analyzing solutions that are currently under development for the different levels of the infrastructure. The talk will not only propose solutions but also support the approaches with concrete experiences mostly developed within the framework of large European research projects.