This work addresses the integrated design of the high temperature steam electrolysis (HTSE) and biomass to liquid (BtL) hybrid process. The comprehensive gate-to-gate analysis includes BtL and hydrogen production on-site operations. Simulations are carried out using commercial process simulation software-ProSimPlus-to allow physical modeling as well as mass and energy balances; modeling is based on standard elementary and user modules and supported by various CEA (French Atomic Energy and Alternative Energies Commission) previous works. The framework for assessment is proposed. Considering productivity, efficiency, cost, and environmental issues, five sustainability, criteria are chosen: carbon matter yield, energy efficiency, greenhouse gas emissions, electrolysis water use, and levelized, biofuels production cost. Simulations results verify that hydrogen input is almost doubling the biogenic carbon conversion into liquid biofuels. They bring out significant secondary energy, saving for HTSE compared to the standard process and clear advantages over alkaline electrolysis considering technical and environmental criteria. HTSE coupling allows a sharp increase in productivity (biofuels/biomass) with a limited increase in cost and environment impact at almost constant primary efficiency.