generates electrical energy and which pursuant to fig3 left hand side is arranged in the interior 34 cavity 34 of the receiver 5 in instances of malfunction for example in the event of an emergency shutdown of the hot gas turbine or at a power failure of the central computer controlling the heliostat system or when during normal operation due to any reason the arrangement 6 located in the region of highly concentrated radiation must be protected from the high heat of radiation one or more smoke cartridges are fired into the path of radiation 7 between the radiation source and the receiver 5 where they diffuse therein and form a smoke fog causing the concentrated light of radiation to be dispersed in the smoke and consequently a reduction in the intensity of radiation impinging upon the receiver this diffusion of the radiation results in the arrangement 6 particularly that region of the arrangement which is located in the focal point of the arrangement 6 no longer being exposed to an excessively high operating temperature thus eliminating the fear of material damage in an advantageous aspect of the invention a firing device is provided on or within the solar tower itself particularly in the upper receiver region.