This study examines how long-term and short-term energy crises may affect heat production in low-carbon District Heating (DH) networks. For this purpose, various scenarios decarbonizing DH network are investigated mainly in two groups, i.e., biomass combustion scenarios and waste heat-based scenarios. The duration of the hypothetical energy crisis is assumed as 3 years (Short-term Energy Crisis) and 10 years (Long-term Energy Crisis), and it is defined as a sharp increase in the electricity and biomass prices compared to the average prices over 2015-2020. Heat Production Cost (HPC), and Break-Even Price (BEP) are calculated and compared in various scenarios. The results show that in both long-term and short-term energy crises, biomass CHP has a significantly better performance compared to biomass HOB and waste heat-heat pump, but it provides much more expensive heat as the end-use product. Biomass HOB and waste heat-heat pump perform very similarly.