In this study, gasification performance and importance of hydrogen production using waste of a tea factory were evaluated. A mathematical model was developed for the gasification system, which includes a water gas shift reactor used for hydrogen purification. The gasifier temperature was 877 °C for the developed model. The model has been validated against experimental data from an 80 kW t h cylindrical downdraft gasifier, given in the literature for syngas composition for three different air-to-fuel ratios. With the developed model, hydrogen production from tea wastes was achieved to yield a higher level by additionally using a water gas shift reactor. Tea waste (1000 kg) was gasified and after the hydrogen purification process, a total of 4.1 kmol hydrogen was achieved, whereas the amount would be 2.8 kmol gas hydrogen if a normal gasification method were used. The validity of the developed model was verified by comparing the experimental results obtained from the literature with the results of the model under the same conditions. After verification of the developed model, the effect of the moisture content of the biomass and the air/fuel ratio on the composition of the product gas were investigated. These investigations were also confirmed by experimental data. The results show that it is important to convert biomass waste into a clean energy source of hydrogen to minimize its environmental impact. © 2019 Serbian Chemical Society. All rights reserved.