Assessment of the economic viability of the integration of industrial waste heat into existing district heating grids

摘要

In many industrial enterprises in the European Union a large amount of waste heat from various processes still remains unused. A recent study in Austria detected a technically feasible industrial waste heat potential of around 15 TWh yearly. This is more than 25 % of the final thermal energy demand of the Austrian industry and about 74 % of the final energy demanded in district heating networks. Reusing industrial waste heat is essential in order to increase the energy efficiency of the European energy system and to reach the 20-20-20 targets of the European Union. However, up to now economic and non-economic barriers are hindering the uptake of this potential. This research aims at analysing the economic viability of the integration of industrial waste heat into existing district heating grids. We investigate different system components, sources of waste heat, return temperatures of the district heating grid as well as the distance between plants and grids, including sensitivity analyses. A techno-economic modelling tool was developed that simulates the integration of industrial waste heat into district heating grids following the concept of Levelized Costs of Heat(LCOH). We find the following highly influencing factors on the economic viability of such projects: the distance between the waste heat sources and the district heating grid, the return temperature of the district heating grid, the available waste heat power, the full load hours of the system as well as the economic assessment period. This underlines the importance of low-temperature heating grids allowing a larger number of waste heat sources to be reused. For many combinations of the stated parameters we calculated LCOH remarkably below 1 ct.EUR/ kWh. This is considerably lower than the current prices for district heat.