TECHNOLOGY FOCUS - BIOLOGY - Preferred Process: The algae used for the production of hydrogen are separated by the light source, preferably sunlight, through a transparent plate. The separation of the gaseous intermediate products hydrogen and oxygen is carried out by the alga medium over a membrane (3), preferably a porous membrane from cross-linked polyethylene. The membrane is fixed on both sides by a hexagonal dense sphere packing. In the method, a multi-layer membrane is used, whose layers are at least partly welded together, preferably in a circular or a honeycomb pattern. The osmotic pressure of carbon dioxide is increased on the gas side of the membrane. The separation of the produced oxygen from the hydrogen takes place through gas liquefaction (8), preferably in the lime-tree procedure. Excess amount of hydrogen and oxygen are used for the production of pure fresh water, preferably under use of waste heat the hydrogenesis step. Hydrogen and carbon dioxide are supplied to the methanogenesis bacteria under anaerobic conditions and/or at a temperature of 60 degrees C. Carbon dioxide is obtained from dry ice, where the dry ice is obtained optionally from air liquefaction, preferably in the lime tree procedure. Carbon dioxide is obtained from carbon dioxide-rich gas flow, preferably from industrial and burning processes. The non-used and/or non-converted carbon dioxide is recovered preferably by a cooling trap and recycled in the process. The developed excess alga and/or bacterial material are periodically or sequentially obtained and a biogas process is carried out for additional methane production. The heat produced from the hydrogenesis step is conducted preferably by a heat exchanger or a heat pump. The heat is transferred between the hydrogenesis step and the methanogenesis step. Preferred Components: The algae used for the production of hydrogen are present in an aqueous solution, which is optionally, periodically or sequentially supplied with nutrients (5). The algae used for the production of hydrogen are green algae, preferably Chlamydomonas reinhardtii. The intra-cellular oxygen is bound in the algae, and is bound preferably during or after the hydrogenesis step. The intra-cellular oxygen is biochemically or chemically bound by the addition of at least a bonding agent. The bonding agent is regenerated after the addition of oxygen. The bonding agent (in biochemical bonding) is myoglobin, porphorine. Myoglobin and/or porphorine are electro-chemically and/or biochemically and/or physically regenerated after the addition of oxygen. The methanogenesis bacteria are provided with an aqueous solution, which is optionally, periodically or sequentially supplied with nutrients. The methanogenesis bacteria exhibits a mixture of the type Methanobacterium thermoautotrophicum, Methanobacillus, Methanobacterium, Methanococcus, Methanosarcinaand Methanothrix. ORGNAIC CHEMISTRY - Preferred Components: The bonding agent (in chemical bonding) is hydrazine and/or a hydrazine salt, preferably iron hydrazine, terpene, preferably alpha -terpene and/or an isoprene and/or its derivatives. In the method, a black membrane is used.    TECHNOLOGY FOCUS - POLYMERS - Preferred Components: The cross-linked polyethylene-membrane is used with an internal layer from poly(acrylamide-tert-butylsulfonic acid). Preferred Components: A plate has a self purification effect (lotus effect) on the darker side, which is optionally provided by a silane coating. EXAMPLE - No suitable example given.