Strategies to decarbonise energy sectors by substituting fossil fuels with renewable energy sources (RES) pose challenges for today’s energy system. RES are mainly decentralised, not always predictable and introduce a high degree of volatility into energy grids. To cope with this challenges, flexible multi-energy-systems (MES) may be beneficial. To assess impacts of high degree of RES on energy grids and derive suitable countermeasures, simulation tools are necessary. In this article we propose a modelling framework suitable to perform a detailed technical assessment of MES. This framework (HyFlow) allows for MES simulation and includes depiction of spatial area and simplification of electricity grids without neglecting its properties. Additionally, we demonstrate the application of HyFlow to assess the impacts of the Austrian energy strategy #mission2030 on the energy grids of an Austrian federal state. We present and analyse two scenarios with various degrees of future generation and demand developments, including sector-coupling technologies, energy storages and electric vehicles. Both scenarios demonstrate that a high degree of renewable electricity generation can be realised with few improvements of the current energy infrastructure. Hybrid technologies such as heat pumps and power-to-gas turned out to be crucial in terms of both, energy efficiency as well as flexibility.