Techno-economic analysis of a hybrid heat recovery-renewable energy system for enhancing power reliability in cement factories in Pakistan

Pakistan is among the top twenty cement producing countries in the world, with an annual capacity of over 44 million tons. The growth of the cement industry in Pakistan is expected to be around 14% over the next five years. Nonetheless, this growth could lead to increased use of fossil fuels, contributing to global warming. This research proposes a novel grid-tied hybrid power supply scheme that can offer a more reliable source of electricity for the cement manufacturing process in Pakistan. The proposed hybrid power system stands out for its unique aspect of using both renewable energy sources and waste heat by integrating a solar thermal power cycle with heat recovery from exhaust gases and wind power turbines. The detailed simulation of the proposed hybrid waste heat recovery-renewable energy (WHR-RE) system is performed in the Transient System Simulation (TRNSYS18) Tool. The objective of the simulation is to identify the optimal size and configuration of the system that can fulfill the required electrical load of the Pakistan Cement factory located in the Kalar Kahar district of Chakwal, Pakistan. The techno-economic analysis indicates that the proposed WHR-RE is economically feasible, providing 40% of the total electricity demand with an annual generation of 109.2 GWh and a net present value of USD 25.69 million. Moreover, this system will reduce the factory's annual electricity bill by USD 19.66 million and mitigate CO₂ emissions by 52.7 thousand tCO₂e/year.