This work presents two methods for evaluating the lateral dispersion coefficient in a fluidized bed for three different fuel types, namely wood chips, pellets and char of pellets. Mixing of the different fuels is also related to the mixing of bed material to evaluate to what extent they are correlated. The experimental work is conducted in fluid-dynamically downscaled fluidized beds and the validity of this approach is shown by replicating an experiment presented in literature which was conducted in a large scale boiler. The two methods, a direct one and an indirect one, are shown to yield similar results which suggest that both of them are robust. The wood chips and pellets are found to behave similarly and to follow the flow of bed material well. On the other hand char particles are found to be less influenced by the flow of bed material and char particles are also more sensitive to changes in the pressure drop over the gas distributor compared to wood chips and pellets. (C) 2014 Elsevier Ltd. All rights reserved.