A process and system for the conversion of biomass under high severity in the presence of a catalyst to produce a bio-oil, olefins, methane, and carbon monoxide (CO). The methane and/or CO can be used to generate hydrogen and the generated hydrogen can be used for hydrotreating the bio-oil. Additionally, or alternatively, a syngas stream, a carbon dioxide-rich stream, and/or a methane-rich stream can be recovered for use in the bio-oil production process and/or for use in a conventional petroleum refinery and/or petrochemical plant.