Externally fired gas turbines (EFGT) are in commercial use since the late 1930s when 2.3MW Escher Wyss plant was commissioned. There are at least four EFGT projects of an electrical output under 100 kW of which results were published. In recent years personnel of Institute of Power Engineering have built the EFGT test rig and executed laboratory tests the system in which the installed generator has electric output of 6 kW. The system consist of radial turbine, centrifugal compressor and permanent magnet generator rotor installed on one shaft, a heat-exchanger with piping, a biomass combustion chamber, an exhaust gases discharge piping system connected to the chimney, additional pressurized air system for turbine startup. In the article the results of laboratory tests of the system are presented. Based on the measured parameters, an economic analysis is carried out in to assess the application potential of the developed micro-scale externally fired gas turbine system fuelled with solid biomass.