Thermo-economic performance evaluation of thermally integrated Carnot battery(TI-PTES) for freely available heat sources

In a scenario driven by non-programmable renewable energy sources (RES) being integrated into the grid, there is a critical need for large-scale energy storage solutions for maintaining grid stability and providing services of frequency regulation as being currently provided by conventional thermal power plants. Among various options, Carnot batteries stand out for their ability to provide GWh scale storage without geographical limitations, at reasonable costs, integrating power to heat to power technologies to thermal energy storage (TES), however at the cost of relatively low Round Trip Efficiencies (RTE). This study delves into a new concept in Carnot battery called Thermally Integrated Pumped Thermal Electricity Storage (TI-PTES) utilizing sCO2 heat pump and power cycles. Thermal integration of heat source in the charging cycle leads to attractive Round Trip Efficiency(RTE) values as compared to conventional PTES. Additionally, using supercritical carbon dioxide (sCO2) as a working fluid offers several advantages of compact designs leading to reduced overall footprint compared to other fluid-based technologies. The study analyzes thermo-economic performance of sCO2 based TI-PTES using an in-house tool WTEMP-EVO; for integration of various industrial and renewable heat sources into the PTES system while exploiting market available thermal energy storage options through a mapping approach.