A heat accumulator having a housing to receive a heat storage medium, a heat storage medium received in the housing, and a heat exchanger, in which a heat carrier fluid can be transported and which is arranged so that heat can be transferred from the heat storage medium to the heat carrier fluid. The heat accumulator comprises an electrical heating means which is configured to convert electrical energy into heat energy. The electrical heating means is arranged so that it heats the heat storage medium during operation, wherein the heat storage medium heated by the electrical heating means is a metal. In addition a corresponding method is disclosed.