NOVELTY - System comprises: at least a first device for the biological production of ethanol, in which carbon dioxide is formed, and at least a second device for chemical conversion of carbon dioxide to a hydrocarbon; a first connection from the first device to the second device; a second connection from the second device to the first device; at least one steam generation device; a third connection; at least one third device for generation of hydrogen; a fourth connection from the first device to steam generation device; a fourth device which is connected with the production of ethanol.    USE - The system is useful for producing aliphatic alcohols (claimed).    ADVANTAGE - The system: is energy efficient; and ensures uniform temperature control.    DETAILED DESCRIPTION - System comprises: at least a first device for the biological production of ethanol, in which carbon dioxide is formed, and at least a second device for chemical conversion of carbon dioxide to a hydrocarbon, which is connected downstream of the first device for the chemical synthesis of a hydrocarbon for the biological production of ethanol; a first connection from the first device to the second device, which passes carbon dioxide formed in the first device into the second device; a second connection from the second device to the first device which passes carbon dioxide formed in the second device into the first device; at least one steam generation device; a third connection arranged between the steam generation device and the first device and passes the steam produced in the steam generation device into the first device; at least one third device for generation of hydrogen, which comprises a fifth connection to the second device, which introduces the hydrogen into the second device, and the third device is configured to generate hydrogen and oxygen from water, and to generate compressed hydrogen and oxygen with a pressure of more than 15 bar; a fourth connection from the first device to steam generation device, which passes the condensate formed in the first device into the steam generation device; a fourth device which is connected with the production of ethanol, such that the generated steam is used for input of thermal energy for the production of ethanol in the first device. An INDEPENDENT CLAIM is also included for preparing aliphatic alcohols, comprising producing a first aliphatic alcohol by a biological process, where carbon dioxide is formed, and the first aliphatic alcohol is ethanol, and reacting carbon dioxide with a short chain hydrocarbon by chemical- or catalytic synthesis. The reaction of the carbon dioxide in the production of the first aliphatic alcohol is downstream and locally separated, and the production of the first aliphatic alcohol and the reaction of the carbon dioxide are connected, such that the carbon dioxide is at least partially used as a product of the production of the first aliphatic alcohol or as reactant for the production of hydrocarbons. The process for producing steam is connected with the production of ethanol such that the steam generated is used for introducing thermal energy for the production of ethanol, and a process for the generation of hydrogen is connected with the production of hydrocarbons, such that the generated hydrogen is used as the reactant for the chemical synthesis of short-chain hydrocarbon. The process for the generation of hydrogen is a procedure based on the electrolysis of water, in which oxygen is formed in addition to hydrogen by electrolysis, which is used for generating steam, where the process is alkaline electrolysis and polymer electrolyte membrane electrolysis.