Technical and economic evaluation, comparison and optimization of a Carnot battery with two different layouts

Abstract

Integrating energy storage systems into electricity distribution systems can improve flexibility, stability and reliability. This issue becomes even more important in renewable resources-assisted energy production systems; because such systems are less reliable due to the intermittent nature of renewable resources. Carnot battery energy storage is a relatively new and emerging approach that is able to solve many challenges of available storage technologies (cost and geographical dependencies). In this regard, in the present article a Carnot battery based on pumped thermal energy storage system (PTESS), organic Rankine cycle (ORC) and vapor heat pump (VHP) has been assessment and discussed in two different modes from the perspectives of thermodynamics, exergy, costing and optimization. In the first case, both charge and discharge modes have a waste heat recovery process (using a regenerator). However, in the latter case, both mentioned modes do not have a waste heat recovery process. Therefore, the purpose of the current article is to examine and compare two different modes of a Carnot battery. Additionally, the minimum value of Levelized cost of storage (LCOS) (as an objective problem) is determined based on the artificial bee colony algorithm. The outcomes revealed that at 120 °C, the LCOS and net investing cost values for the considered storage configuration were almost 0.293 USD/kWh and 5450 thousand USD. Furthermore, a comparison of the considered storage configuration with the no-regenerators mode confirmed that the embedding of regenerators in both the charge and discharge sub-cycles could reduce the LCOS value by nearly 10 %.