Integration of concentrated solar power plants with 5th generation district heating systems using waste heat recovery: A techno-economic and environmental analysis

The decarbonization of district heating systems remains a major challenge due to the continued reliance on fossil fuels for heat supply. This study proposes an integrated concentrated solar power (CSP) and fifth-generation district heating (5GDH) system that directly utilizes the low-temperature cooling water leaving the CSP condenser as the heat source for the district heating network. A booster heat pump upgrades the recovered heat to the required supply temperature, while thermal energy storage (TES) ensures continuous operation under varying solar conditions. The system is evaluated through hourly energy, exergy, environmental, and techno-economic analyses. The results show that the receiver provides an average thermal input of 77.5 MWₜ (679 GWh/year), producing 324.5 GWh/year of electricity and 80.5 GWh/year of useful heat. The overall energy efficiency ranges from 45% to 75%, with an annual average of 59.6%, while the exergy efficiency varies between 38% and 52%. CO₂ emissions are reduced by approximately 96 kt/year when the heat pump is powered by the grid and 107 kt/year when powered by CSP-generated electricity. The corresponding levelized cost of electricity and levelized cost of heat are 0.163 $/kWh and 0.075 $/kWh, respectively. The proposed configuration demonstrates that direct utilization of condenser waste heat can simultaneously provide electricity and low-temperature heat while improving the overall energy performance of CSP-based district heating systems.