Thermodynamic, economic, and environmental analysis of a novel hybrid energy storage system: Psuedo-dynamic modeling approach

High-temperature heat and power storage is a promising recent proposed energy storage technology, just suffering from low electrical efficiency. The combination of this system with an organic Rankine cycle can be a very clever measure for addressing this drawback of the technology and achieving higher electrical efficiency. The present article presents a very thorough feasibility study on this innovative hybrid energy storage solution digging into its thermodynamic performance proficiency, cost-effectiveness, environmental effectiveness, and, more importantly, the effects of partial load operation on its techno-economic indices. For the latter, the effects of load variations on the mass flow rate, pressure ratio, and isentropic efficiency of the turbomachinery are considered to give the most accurate possible picture of the technical, environmental, and economic performance aspects of the system in dynamic operating conditions. In addition to a concrete answer regarding the feasibility of the technology, the further findings of the article would be strongly beneficial for finding the optimal performance of the storage technology when working in a renewable power plant with ups and downs in power outputs. As the results show, the annual averaged electrical efficiencies of the system is 27.07/43.01% with/without considering the impact of the dynamic condition. The levelized cost of storage of the system will be 621.5 €/MWh and 390 €/MWh, when considering and not considering the impacts of the partial load operations, respectively.