We study decentralized, renewable energy systems at building, district and urban scale. We model geo-dependant en-ergy demand, renewable potentials and other heat resources. We develop new methods, models and tools for the holistic analysis and optimisation of urban energy systems, with emphasis on energy hub and multi-energy systems. Models and data are embedded in the Holistic Urban Energy Simulation Platform (HUES). A holistic approach for urban building design and design space exploration is pursued, considering building shape, urban microclimate effects (in close collaboration with the urban climate group of the (Empa Multiscale Building Physics Laboratory), control and facility energy management as well as energy systems at regional or even national level. Multi-energy concepts will include energy supply for mobility and respective issues of power to gas. The analysis and optimization framework and associ-ated tools are extended to urban comfort and utility aspects.