Processes for making hydrogen and optionally carbon monoxide and their integrations in a Carbon-to-Liquids plant are disclosed. A first syngas produced by a first syngas generator is converted in a hydrocarbon synthesis process to hydrocarbon products, oxygenates and product water comprising dissolved oxygenates. The first syngas generator may use partial oxidation, reforming, gasifying, or pyrolysis of any solid, liquid or gaseous carbonaceous feedstock. The product water may be treated, for example by distillation and/or by stripping, to form an oxygenates-rich stream which comprises a reforming reactant and oxygenates originating from the product water. Oxygenates from the oxygenates-rich stream fed to a second syngas generator are converted under reforming conditions to form at least hydrogen. The hydrogen formed by reforming may be supplied to one or more units using hydrogen within a Carbon-to-Liquids plant.