NOVELTY - Preparing methanol comprises: a step (10) for obtaining a first stream of synthesis gas, where the first synthesis gas stream mainly comprises hydrogen, water, carbon monoxide and carbon dioxide; a step (14) of adding a quantity of hydrogen in the first synthesis gas stream to form a second synthesis gas stream; and a step (16) of producing methanol from the second synthesis gas stream by reaction of carbon monoxide and hydrogen gas.    USE - The process is useful for producing methanol.    ADVANTAGE - The improved process produces methanol in high yield in high purity with low emission of carbon dioxide gas.    DETAILED DESCRIPTION - Preparing methanol comprises: a step (10) for obtaining a first stream of synthesis gas, where the first synthesis gas stream mainly comprises hydrogen, water, carbon monoxide and carbon dioxide; a step (14) of adding a quantity of hydrogen in the first synthesis gas stream to form a second synthesis gas stream; and a step (16) of producing methanol from the second synthesis gas stream by reaction of carbon monoxide and hydrogen gas, where the second synthesis gas stream comprises a molar fraction of carbon dioxide of greater than 15 mol.%, the amount of hydrogen is added after the step for obtaining the first synthesis gas stream and is chosen for the production of methanol from the second synthesis gas stream by reacting carbon monoxide and hydrogen and by reaction of the carbon dioxide and hydrogen.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic representation of process for the preparation of methanol.    Step for obtaining a first stream of synthesis gas (10)    Step of adding a quantity of hydrogen in the first synthesis gas stream to form a second synthesis gas stream (14)    Step of producing methanol from the second synthesis gas stream (16)    Step for producing the amount of hydrogen added to the first stream of synthesis gas by electrolysis of water (22)    Substep for producing an intermediate stream containing methane by gasification of carbonaceous material (26)    Substep of autothermal reforming or steam reforming. (30)