A small mobile agricultural residue gasification unit for decentralized CHP (combined heat and power) production is designed and constructed within the framework of the SMARt-CHP LIFE+ project. This unit applies the technology of biomass gasification coupled with an ICE (internal combustion engine) based generator-set for CHP production. The unit is sized for a maximum thermal output of 12 kW in addition to approximately 5 kW electrical output. Four different locations close to biomass feedstock origin in rural areas of Western Macedonia in Greece, two in Ptolemaida and two in Amyntaion, were selected for the demonstrative operation of the unit. Peach, olive and grape residues were utilized as biomass feedstocks while the unit operated continuously on a 24/7 basis. The present paper describes the, unit performance in terms of operation stability, application of different agricultural residues as well as the energy output of the process. The results show the effect of different types of biomass feedstock, gasification parameters and engine intake mixture to long-term operation and energy output while the obtained data will aid in the direction of CHP systems scale-up and optimization towards possible commercialization. (C) 2013 Elsevier Ltd. All rights reserved.