TECHNOLOGY FOCUS - ELECTRICAL POWER AND ENERGY - Preferred System: The container is a flexible tube (S) in which the photovoltaic membrane forms an axial partition. The tube has a flexible transparent insert (LE) extending axially above the photovoltaic membrane, serving as an optical waveguide. The photovoltaic membrane divides the tube into two water chambers (WKA, WKK) through which water flows in the same direction and carries the dissociation gases formed in the photovoltaic system (PS) to gas exchangers. The transparent insert is in the form of a plastic lens (KL) with a circle segment-shaped cross section. The photovoltaic membrane has proton gates at regular intervals in the membrane. The tube has a reflective surface (RS) on the inside in the region of the water chambers. The reflective surface comprises an aluminum layer with a corrosion-resistant silicon dioxide coating. The tube has a Winston-type collector structure (WKA) on the inside in the region of the water chambers. The tube is laid out in a shaped panel, especially in the form of a flat spiral. Water flowing through the tube is passed through an integrated heat exchanger. Sunlight is transmitted to the photovoltaic membrane through a concentrator. The dissociation gases are passed to an integrated fuel cell system.    TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred System: The modified titanium dioxide layer (TS) with oxygen-catalyzing properties is doped with nitrogen, sulfur and/or carbon. The modified dioxide layer (TS) with hydrogen-catalyzing properties contains nickel-molybdenum catalyst particles. The titanium dioxide layers contain a photoactive dye. The photovoltaic membrane (PM) is flexible, especially comprising a flexible central support of titanium foil. The integrated photovoltaic structure (PVS) comprises a tandem thin-layer solar cell, especially a simplified copper-indium (sulfide, selenide) tandem solar cell (CIS) or an amorphous or crystalline silicon solar cell. In the solar cell, the normal zinc oxide window layers are replaced by the titanium dioxide layers and the current-collecting elements are removed. The dissociation gas formed by the modified dioxide layer with hydrogen-catalyzing properties is hydrogen peroxide.