A method including: (i) operating a pumped-heat energy storage system (“PHES system”) in a charge mode to convert electricity into stored thermal energy in a hot thermal storage medium (“HTS medium”) by transferring heat from a working fluid to a warm HTS medium, resulting in a hot HTS medium, wherein the PHES system is further operable in a generation mode to convert at least a portion of the stored thermal energy into electricity; and (ii) heating the hot HTS medium with an electric heater above a temperature achievable by transferring heat from the working fluid to the warm HTS medium.