This is a review of the possibilities for a direct conversion of solar energy to chemical energy. By this conversion a natural flux will be fed in an artificial reservoir, from which high-quality energy can be tapped when necessary. After discussing the chemistry of photosynthesis in plants, the structure of the pertinent 'machine' is described with emphasis on the photosynthetic membranes.
Energy storage is the result of the blocking of back-reactions.
Having understood essential functions of the natural membranes one can design artificial devices, of which three are discussed. They are only of academic interest. Despite the considerable progress in the realization of such structures, the stabilization of photo-charge in a product like hydrogen is not yet possible.