NOVELTY - Solar-driven apparatus (300) comprises: a cavity (305) having at least one optical window (310) for collecting electromagnetic radiation associated with solar energy impinging on the window; a reaction assembly located inside cavity, for carrying out electrolysis process of at least one raw fluid utilizing energy derived partially from solar radiation and partially from electric source; at least one ingress unit (320) operative to allow introduction of raw fluid into apparatus; and at least one egress unit (325) operative to allow exit of electrolysis process products from apparatus.    USE - The solar-driven apparatus is useful for carrying out an electrolysis of raw fluid including carbon dioxide and/or water for generating electricity (all claimed).    ADVANTAGE - The solar-driven apparatus: generates clean electricity using solar energy with cost effective storage allowing per-demand operation, on a continuous basis; reduces carbon dioxide emission by using it as feedstock for fuel generation; reduces the need for sequestration of carbon dioxide captured in power plants and other carbon dioxide emitting facilities; and generates a viable and cost competitive alternative for liquid fuel for transportation.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for:    (1) a solar-driven reaction assembly, adapted to be located in a solar-driven apparatus for carrying out an electrolysis process of raw fluid in it; and    (2) carrying out an electrolysis of at least one of carbon dioxide and/or water in the solar-driven apparatus, comprising: exposing the optical window to the solar radiation; introducing raw fluid comprising carbon dioxide and/or water into the apparatus, thus causing an electrolysis process where energy required for the process is provided partially from the solar energy and partially from an electric source; and allowing withdrawal of products obtained in the electrolysis process away from the apparatus.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic layout of solar-driven apparatus for converting carbon dioxide to syngas, where the reaction units are exposed to direct solar radiation.    Solar-driven apparatus (300)    Cavity (305)    Optical window (310)    Ingress unit (320)    Egress unit (325)