Germanium TPV cells have been manufactured by MOVPE and have been included in a tungsten emitter-based solar thermophotovoltaic system. This system uses concentrated power from the sun for heating a cylindrical-shaped tungsten emitter. The radiation spectrum of tungsten is better matched to the Ge TPV cell spectral response than the sun's spectrum. The complete system has been characterized under real conditions. For this purpose, 8 TPV cells have been assembled in a series-connected array, which makes up an octagonal receptor structure around the cylindrical tungsten emitter. A loss analysis is presented in order to find the efficiency contribution of each part of the system and a near-future improved system efficiency has been estimated.