Heat transfer system for transferring heat from a thermal conversion system to a heat consuming system , comprising: - a heat storage salt, - a heat storage system, comprising a storage container for the heat storage salt, - a heat exchange system which heats the heat storage salt to a temperature in excess of 350 °C with heat produced by the thermal conversion system, - a circuit connecting the heat storage system to the heat exchange system and being arranged for circulating the molten heat storage salt between the heat exchange system and the heat storage system, the circuit comprising a pump for pumping the molten salt from the storage container to the heat exchange system , - a heat exchanger transferring the heat of the molten salt to the heat consuming system , the heat storage mass being convertible from a solid to a liquid phase by adding heat and from a liquid to a solid state by releasing heat, wherein the storage container comprises - an upper wall , a bottom wall and a lateral wall extending in between the upper and the bottom wall, the lateral wall has a downwardly narrowing, truncated conical and circumferentially walled shape, with an inclination angle of at least 20 degrees versus a vertical plane, - heating means comprising electrical heating elements that are switchable on and off and that are provided for converting the heat storage mass in the storage container • from the solid to the liquid phase by adding heat to the heat storage mass when the heating means are switched on, and • from the liquid to the solid phase by cooling down the liquid heat storage mass when the heating means are switched off. - a heat storage salt, - a heat storage system, comprising a storage container for the heat storage salt, - a heat exchange system which heats the heat storage salt to a temperature in excess of 350 °C with heat produced by the thermal conversion system, - a circuit connecting the heat storage system to the heat exchange system and being arranged for circulating the molten heat storage salt between the heat exchange system and the heat storage system, the circuit comprising a pump for pumping the molten salt from the storage container to the heat exchange system , - a heat exchanger transferring the heat of the molten salt to the heat consuming system , - an upper wall , a bottom wall and a lateral wall extending in between the upper and the bottom wall, the lateral wall has a downwardly narrowing, truncated conical and circumferentially walled shape, with an inclination angle of at least 20 degrees versus a vertical plane, - heating means comprising electrical heating elements that are switchable on and off and that are provided for converting the heat storage mass in the storage container • from the solid to the liquid phase by adding heat to the heat storage mass when the heating means are switched on, and • from the liquid to the solid phase by cooling down the liquid heat storage mass when the heating means are switched off. • from the solid to the liquid phase by adding heat to the heat storage mass when the heating means are switched on, and • from the liquid to the solid phase by cooling down the liquid heat storage mass when the heating means are switched off. <EOS>