We examine the carbon mitigation potential of operational adjustments for a German university campus. To this end, we compare the modeled cost-optimal operation with CO2-minimizing dispatch plans where different limits for the additional, specific CO2 mitigation costs are set. At first, the operational mitigation potential of today’s combined heat and power (CHP) driven energy system is analyzed. Then we examine the possible effects of increased flexibility of this multi-energy system by adding heat pumps and heat storage. We include a detailed account of today’s operational cost structure including taxes and subsidies. To correctly represent the CO2 footprint of consumed electricity from the grid, we consider the CO2 intensity of Germany’s electricity mix as time-dependent. This is important to correctly honor the impact of the multi-energy system’s flexibility. We find that given the current regulatory environment, without considering investment costs, large CO2 reductions compared to the modeled cost-optimal operation can only be achieved for specific CO2 mitigation costs above 150\euro/t. Small reductions can be obtained at much lower cost when a heat pump operates in parallel with the CHP. However, for all scenarios the CO2 reductions can only be realized by exploiting periods with low CO2 intensity of the grid’s electricity.