TECHNOLOGY FOCUS - ELECTRONICS - Preferred Components: The fuel cell is a low temperature polymer electrolyte membrane fuel cell and that the electrolyzer is a reversed-powered low-temperature polymer electrolyte membrane fuel cell. At least one water storing medium is arranged in the electrolyzer. Preferred Method: The substrate is at least partially hydrogenated in the presence of a suitable catalyst with the extended pi -conjugated system in the first chemical reactor at a temperature of 50-180 degrees C and a pressure of 2-200 bar. The hydrogen generated in the electrolyzer is used without intermediate storage for at least partial hydrogenation of at least one substrate with the extended pi -conjugated system in the first chemical reactor. The method comprises introducing heat generated in at least partial hydrogenation of at least one substrate with the extensive pi -conjugated system in the first chemical reactor into a heating system of the stand alone building. The partially hydrogenated substrate with the extended pi -conjugated system is dehydrated under heat supply in the second chemical reactor. The heat required for the dehydrogenation from the heating system is used for the solitary building. The dehydrated substrate from the second chemical reactor in the second reactor is recycled into the electrolyzer through the storage tank. The water in the fuel cell formed during the oxidation of hydrogen is transferred into the electrolyzer. The heat released in the fuel cell is introduced into the heating system and the released electrical power to the power grid of the stand alone building or into an external power line. The oxygen required for the oxidation of hydrogen in the fuel cell is externally supplied into the fuel cell in the form of air. The method includes supplying an additional electric power, if required from another power source into the electrical network of the stand alone building. The method includes supplying back additional electric power if required from the fuel cell into the external electrical grid.    TECHNOLOGY FOCUS - INSTRUMENTATION AND TESTING - Preferred Components: At least one electrolyzer is connected with at least one fuel cell through the first chemical reactor, the storage tank and the second chemical reactor.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: The substrate with the extensive pi -conjugated system includes polycyclic aromatic hydrocarbon, polycyclic heteroaromatic hydrocarbon and/or pi -conjugated organic polymer, preferably condensed heteroaromatic hydrocarbons with nitrogen, sulfur or oxygen heteroatom, in which the substituted or unsubstituted hetero atoms are present. The condensed heteroaromatic ring systems comprise hydrocarbon of 6-30C, preferably 12C. The hetero atoms are substituted with at least one alkyl group, at least one aryl group, at least one alkenyl group, at least one alkynyl group, at least one cycloalkyl group and/or at least one cycloalkylene group, preferably 1-30C alkyl, preferably 2-5C alkyl group. The arrangement comprises use of N-ethylcarbazole, N-n-propylcarbazole or N-iso-propylcarbazole as the substrate with the extended pi -conjugated system.