Energy-economic assessment of reduced district heating system temperatures

It is in the DNA of district heating (DH) systems that low temperatures are crucial for efficiency, guaranteeing cost competitiveness and integrating alternative heat sources. The general conviction within the DH community is, that reduced temperatures have positive effects for the whole system and economic benefits can be expected. However, there is a lack in evidence-based data to evaluate these effects in monetary terms. The innovative approach of this work is to analyze key characteristics for different technologies by means of energy-economic assessments to show evidence-based energy-related and monetary benefits of reduced system temperatures. The proven benefits should increase the motivation and conviction of utilities and customers in low-temperature systems, both for reducing system temperatures in existing networks and for new networks. The key indicator cost reduction gradient (CRG), introduced in previous work, was applied for the energy-economic assessment of reduced system temperatures. In total, investigations of nine heat generation technologies, the DH network itself and four storage types are presented. The CRGs for the heat generation technologies varies from 0.08 to 0.67 €/(MWh·°C). In the case of alternative heat generation technologies such as heat pumps and solar thermal, a higher sensitivity of the monetary effects compared to traditional heat generation technologies can be observed. Here, higher economic benefits and monetary savings can be expected in future DH networks.