The paper focuses on the assessment of using ligno-cellulosic biomass in a fluidized bed gasifier, available within a distance of 50 km, in units with capacity approximately 3 MWe. The main objective of the experiments was to evaluate the effect of partial replacement of inert bed material (sand) with a material catalytically active (dolomitic limestone) on the composition and purity of produced gas and the input fuel energy conversion into the energy chemically bound in the producer gas.