A technical and economical comparison of excess heat transport technologies

The use of industrial excess heat to provide environmentally friendly and efficient heat for heating purposes can be part of the solution to achieve the climate goals of the European Union. CO2 emissions from heating sector have to be dramatically reduced to reach ambitious CO2 targets. In current installations in the EU, excess heat is transported to consumers primarily via district heating. However, the construction of district heating networks is capital-intensive and time-consuming. Depending on the framework conditions, other transport technologies may make more sense. In literature, there is no comprehensive overview that compares areas of application and technical framework conditions and notably carries out an economical comparison of technology. Here, we close this gap and conduct a qualitative and quantitative technical and an economical comparison of new and existing excess heat transport technologies. Based on comprehensive literature review, we screen available technologies and select four technologies for further analysis (district heating, sewer networks, absorption cycles and phase -change materials). We determine the most economical solution for approx. 450,000 combinations of transport distance and excess heat amount and also perform two sensitivity analyses. Our results show that the transport costs for DH are very high (>20ct/kWh) for small amounts of excess heat (less than 1000 MWh). In conclusion, district heating is an economic option for transporting heat, but for distances shorter than 6 km and low excess amounts lower than 1,000 MWh other technologies are more favorable.