Global energy security relies on fossil-based resources that are affiliated with the source of global warming, apart from punches of political and economic instabilities. Biomass is a promising alternative carbonaceous feedstock used for the production of clean energy that could have the potential to substitute for fossil fuels. This study aims to present a conceptual design that considers the criteria to identify the upper theoretical limits of biomass conversion, thus providing the potential approach to the conversion of three biomass (by-products: dry molasses, dry bagasse, and dry filter cake) through gasification, in order to contribute the biomass carbon-capturing by the model assessment of stoichiometric mass conversion and energy efficiency indicators into simple thermodynamic energy vectors, such as alcohols, alkanes, and syngas (a mixture of carbon monoxide and hydrogen). Modeling plays up the importance of stoichiometric efficiency of biomass conversion with the supply of oxygen and hydrogen. This realizes that the multi-product diversification of feedstock into syngas, hydrocarbons, and alcohol through integrated process schemes could have the potential to fill the energy gap and help to manage environmental load. In regard to biomass conversion results, the mass conversion and energy conversion efficiencies of dry bagasse have better conversion potential than molasses and F. cake (% mass conversion = 129 in syngas, 54.4 in alkane, and 43.4 in alcohol; % energy conversion = 94.3 in syngas and 93.3 in alkane and alcohol).