A two-stage high-temperature steam plasma system is analyzed experimentally for the production of high-hydrogen content product gas obtained from biomass. The first stage uses contact glow discharge electrolysis (CGDE) to convert an electrolyte into a steam, mainly composed of steam and a small fraction of hydrogen and carbon dioxide. The second stage uses the output stream from the first stage as the gasifying agent to produce a steam plasma to gasify the biomass. Measurements show molar fractions of hydrogen in the product gases in excess of 50% for six different types of biomass tested. The experimental results are also used to validate a thermodynamic model of the combined process. The model is used to analyze the effect of feedstock mass flow rate on product gas quality. Copyright (C) 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.