A novel staged gasification process aiming to produce heat and power from biomass residue materials has been investigated. The process comprises a fast pyrolysis reactor, coupled with an autothermal catalytic reformer to convert the pyrolysis vapors into a clean fuel gas. Because of the relatively low temperature in the first stage, inorganic contaminants are retained in the fast pyrolysis char byproduct, enabling the use of catalysts in the second stage to produce a virtual tar free product gas. The char byproduct is combusted in the pyrolysis system at moderate temperature, thus preventing potential ash-melt problems. The influence of the air-fuel ratio and mixing behavior, the catalyst composition, and the biomass composition on the process performance were determined using a 1-5 kg/h experimental setup. Six biomass materials ranging from clean wood to sewage sludge were converted without any operational problems. Tar concentrations below 10 mg/Nm(3) could be obtained, which is sufficiently low for direct utilization in a gas engine. The hydrocarbon reforming efficiency appeared uniform, irrespective of the biomass type. However, the overall cold gas efficiency did depend on biomass type, with a maximum of 65% for clean wood, and 55% for the residual biomass materials. The overall energetic efficiency is determined primarily by the degree of char production in the pyrolysis stage.