Pumped　thermal　electricity　storage　is　a　thermo-mechanical　energy　storage　technology　that　has　emerged　as　a　promising　option　for　large-scale　(grid)　storage　because　of　its　lack　of　geographical　restrictions　and　relatively　low　capital　costs.　This　paper　focuses　on　a　10　MW　Joule-Brayton　pumped　thermal　electricity　storage　system　with　liquid　thermal　stores　and　performs　detailed　conventional　and　advanced　exergy　analyses　of　this　system.　Results　of　the　conventional　exergy　analysis　on　the　recuperated　system　indicate　that　the　expander　during　discharge　is　associated　with　the　maximum　exergy　destruction　rate　(13%).　The　advanced　exergy　analysis　further　reveals　that,　amongst　the　system　components　studied,　the　cold　heat　exchanger　during　discharge　is　associated　with　the　highest　share　(95%)　of　the　avoidable　exergy　destruction　rate,　while　during　charge　the　same　component　is　associated　with　the　highest　share　(64%)　of　the　endogenous　exergy　destruction　rate.　Thus,　the　cold　heat　exchanger　offers　the　largest　potential　for　improvement　in　the　overall　system　exergetic　efficiency.　A　quantitative　analysis　of　the　overall　system　performance　improvement　potential　of　the　recuperated　system　demonstrates　that　increasing　the　isentropic　efficiency　of　the　compressor　and　turbine　from　85%　to　95%　significantly　increases　the　modified　overall　exergetic　efficiency　from　37%　to　57%.　Similarly,　by　increasing　the　effectiveness　and　decreasing　the　pressure　loss　factor　of　all　heat　exchangers,　from　0.90　to　0.98　and　from　2.5%　to　0.5%　respectively,　the　modified　overall　exergetic　efficiency　increases　from　34%　to　54%.　The　results　of　exergy　analyses　provide　novel　insight　into　the　innovation,　research　and　development　of　pumped　thermal　electricity　storage　technology.　©　2021　Elsevier　Ltd