NOVELTY - The method comprises passing a heat transfer medium with the loss of thermal energy to a heat storage medium through a primary side of a first heat exchanger while the heat storage medium is conducted by a cold storage (6) through a secondary side (10) of the heat exchanger in a hot storage, and providing a second heat exchanger (3, 4) in a second stage, where the second heat exchanger is located on the primary side upstream or downstream of the first heat exchanger.    USE - The method is useful for storing a thermal energy in a solar thermal power plant such as Andasol 1, 2 and 3 in Spain.    ADVANTAGE - The method is capable of effectively and economically storing the thermal energy in the solar thermal power plant.    DETAILED DESCRIPTION - The method comprises passing a heat transfer medium with the loss of thermal energy to a heat storage medium through a primary side of a first heat exchanger while the heat storage medium is conducted by a cold storage (6) through a secondary side (10) of the heat exchanger in a hot storage, and providing a second heat exchanger (3, 4), in a second stage, located on the primary side upstream or downstream of the first heat exchanger and by which a larger or a smaller mass flow of the heat storage medium as in the first stage of the cold storage is passed into the hot storage. The first heat exchanger is a low temperature heat exchanger. The heat storage medium is divided into two mass flows before reaching the hot storage. One of the mass flows is passed into the hot storage and a first intermediate storage and other via the secondary side of an additional high temperature heat exchanger whose primary side is located upstream of the primary side of the low temperature heat exchanger and is traversed by the heat transfer medium with loss of thermal energy to the heat storage medium. The heat storage medium is additionally combined of two mass flows before reaching the intermediate storage, where one of the mass flows is fed from a second intermediate storage and the other from the secondary side of the low temperature heat exchanger and by which the secondary side of an additional average temperature heat exchanger is conducted and is traversed by the heat transfer medium with the loss of thermal energy to the heat storage medium, where the primary side of the additional average temperature heat exchanger is present between the primary side of the high-temperature heat exchanger and the low-temperature heat exchanger. The high temperature heat exchanger flows through a primary side of superheated steam. INDEPENDENT CLAIMS are included for:    (1) a method of recovering a thermal energy from a heat storage medium in a solar thermal power plant; and    (2) a device for storing and recovering a thermal energy in solar thermal power plants.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic view of a storage system.    Steam turbine (2)    Second heat exchanger (3, 4)    Cold storage (6)    Bypass line (8)    Secondary side of the heat exchanger. (10)