The invention relates to a storage tank (1) for holding a fluid (5) that has a temperature of at least 200°C, said tank having an outer shell (4), an inner shell (2) and a thermal insulation layer (3) lying between said shells. The invention is characterised in that the inner shell (2) is designed in the form of a vertical inverted cone. The invention also relates to the use of a storage tank (1) of this type for storing energy in solar thermal power plants and for retrofitting in conventional storage tanks.
