This　paper　examines　the　passibility,　performance　limits,　and　associated　costs　for　a　self-sustained　relay　to　transmit　its　own　covert　information　to　a　destination　on　top　of　forwarding　the　source＇s　information.　Since　the　source　provides　energy　to　the　relay　for　forwarding　its　information,　the　source　does　not　allow　the　relay＇s　covert　transmission　and　to　detect　it.　Considering　the　time　switching　(TS)　and　power　splitting　(PS)　schemes　for　energy　harvesting,　where　all　the　harvested　energy　is　used　for　transmission　at　the　self-sustained　relay,　we　derive　the　minimum　detection　error　probability　xi*　at　the　source　based　on　which　we　determine　the　maximum　effective　covert　rate　Psi*　subject　to　a　given　covertness　constraint　on　xi*.　Our　analysis　shows　that　xi*　is　the　same　for　the　TS　and　PS　schemes,　which　leads　to　the　fact　that　the　cost　of　achieving　Psi*　in　both　the　two　schemes　in　terms　of　the　required　increase　in　the　energy　conversion　efficiency　at　the　relay　is　the　same,　although　the　values　of　Psi*　in　these　two　schemes　can　be　different　in　specific　scenarios.　For　example,　the　TS　scheme　outperforms　the　PS　scheme　in　terms　of　achieving　a　higher　Psi*　when　the　transmit　power　at　the　source　is　relatively　low.　If　the　covertness　constraint　is　tighter　than　a　specific　value,　it　is　the　covertness　constraint　that　limits　Psi*,　and　otherwise,　it　is　upper　hound　on　the　energy　conversion　efficiency　that　limits　Psi*.