Long-term　energy　storage　and　carbon　capture　technologies　are　pivotal　in　managing　renewable　energy　surpluses　and　achieving　carbon　neutrality.　This　paper　proposes　a　Carnot　battery　system　integrating　calcium-looping　thermochemical　energy　storage　with　a　coal-fired　power　plant.　The　system　utilizes　excess　electricity　from　the　grid　for　energy　input,　facilitating　long-term　energy　storage,　achieving　carbon　capture,　and　reducing　coal　consumption　in　the　power　plant.　An　optimization　framework　is　developed,　incorporating　component　thermodynamic　models　and　optimization　algorithms,　to　maximize　the　coal　savings　in　plants　and　energy　efficiencies　of　the　Carnot　battery　system.　During　the　energy　release　process,　the　carbonator　partially　replaces　the　reheat　load　of　the　boiler,　necessitating　retrofitting　of　the　boiler＇s　heating　surface　to　ensure　normal　operation.　The　base　system　demonstrates　a　CO2　2　capture　capacity　of　3.23　MJ/kg　and　a　reduction　in　coal　consumption　by　7.07　%.　The　roundtrip　efficiency　and　comprehensive　efficiency　of　the　base　system　are　36.93　%　and　37.91　%,　respectively.　The　relatively　low　energy　efficiency　is　primarily　due　to　the　deactivation　of　circulating　adsorbents　and　the　limited　efficiency　of　the　subcritical　coal-fired　power　plant.　By　incorporating　an　additional　recarbonation　step　to　mitigate　adsorbent　deactivation,　the　system＇s　comprehensive　efficiency　is　improved　to　42.20　%.　Further　improvements　in　system　efficiency　can　be　achieved　by　using　modified　adsorbents　with　high　cycling　stability　instead　of　natural　limestone　and　by　coupling　the　system　with　more　efficient　ultra-supercritical　units　instead　of　the　investigated　subcritical　units.　This　study　offers　valuable　insights　into　the　development　of　long-term　energy　storage　solutions　and　multifunctional　Carnot　battery　technology.