Achieving emission reduction through the utilisation of local low-grade heat sources in district heating networks

Decarbonising heat provision is paramount in the global shift towards sustainable energy, and waste heat utilisation presents a transformative opportunity, especially in areas of industrial activity. Accordingly, this study examines the performance of District Heating Networks (DHNs) integrated with unconventional heat sources, specifically mine water and industrial waste heat, aiming to derive a comprehensive understanding of the techno-economic and environmental implications of various DHN configurations. To this end a refined network dynamics simulation model has been developed and employed to evaluate the cost and performance of several network size and heat source combinations, with a case study carried out for Barnsley, UK. Results indicate that large networks can achieve an average thermal efficiency of approximately 87%. Networks utilising mine water have a Levelized Cost of Heat (LCOH) in the range 11.6 – 11.9 p/kWh; introducing industrial waste heat reduces this to 10.6 – 10.7 p/kWh. Additionally, waste heat integration lowers the carbon factor of the supplied heat to 0.05 kgCO2/kWh. Transitioning from boilers to district heating in the region covered by the case study networks showed a marginal emission reduction ranging from 44.76% to 83.46%. The gas price at which these networks achieve economic viability varies from 8.6 to 8.8 p/kWh. In conclusion, the DHNs proposed, especially when augmented with industrial waste heat, emerge as a promising solution for areas like Barnsley in their pursuit of sustainable heating. These findings are pivotal for policymakers and local governing bodies as the UK gears up to meet its 2050 net-zero ambitions.