An energy accumulator for storing electrical energy in the form of heat energy comprising an electric heater for converting electrical energy into heat energy, a heat accumulator for storing the heat energy of the electric heater, and a heat exchanger for emitting heat energy from the heat accumulator. The heat accumulator comprises, at least, a plurality of metal rods arranged upright and serving to store heat energy from the electric heater; a base; and multiple supporting units, wherein each supporting unit supports one of the metal rods and is connected with the base. Furthermore described is a corresponding method for operating an energy accumulator of this type.