This paper presents the first combustion system, which has been designed for the use of biomass derived product gases in micro gas turbines. The operating performance of the combustion system and of the micro gas turbine Turbec T100 was analyzed experimentally with synthetically mixed fuel compositions. Reliable start-up procedures and steady-state operation were observed. The Turbec T100 reached an electrical power output of 50 to 100 kW(el) with a lower heating value of 5.0 MJ/kg. Compared to natural gas, the electrical power output was noticeably higher at constant turbine speeds. Therefore, operation was limited by the power electronic at low speeds, while a second limitation was compressor surging at high speeds. To avoid surging, the turbine outlet temperature had to be reduced at turbine speeds between 64,400 rpm and its maximum of 70,000 rpm. The pressure losses across the FLUX-combustion chamber remained below 4%, which corresponds to a reduction of 30% compared to the Turbec combustion chamber fired with natural gas. Low pollutant emissions, i.e. CO < 30 ppm, NOx < 6 ppm and unbumt hydrocarbons <1 ppm, were obtained over the whole operating range. Further optimization potential of the Turbec T100 was analyzed numerically. Neglecting compressor surging and the limitations of the power electronic, the numerical simulations predicted a maximum power output of 137 kW(el). The ability of the micro gas turbine to run with low calorific fuels is demonstrated and optimization potential is specified. (C) 2015 Elsevier Ltd. All rights reserved.