Due to the tremendous effects of climate change, the goal of a climate-friendly energy supply has developed into the main task of the energy sector. Today climate neutrality is a central issue at social, political and economic levels. It is a sector coupling issue, requiring renewable energies in electricity, mobility and heat supply. While the heat sector contributes the largest share to final energy demand of German municipalities, it is also the sector for which the path towards climate neutrality will be most challenging. This study presents pathways for large cities for the transition from fossil to renewable heat supply based on the example of Rostock. A detailed, fully-physical simulation model for Rostock’s district heating was developed considering different potential heat sources including heat pumps, industrial and process heat, incineration of sewage sludge, waste and solid biomass as well as geothermal and solar thermal plants. Additionally, thermal energy storages have been integrated into the model. The study highlights the importance of simulation models in evaluating the feasibility of energy systems and emphasizes the need for incorporating detailed information in these models to obtain accurate results.Multiple scenarios have been investigated in order to analyse the interplay of heat generation, storage and the annual course of heat consumption. Five final concepts were derived meeting the requirement of climate-neutral heat supply. Although the results show that each variant has advantages and disadvantages, heat generators that make technical and economic sense in all cases were identified. The implementation of these is recommended.