This paper describes the test and the results of a first prototype solar powered gas turbine system, installed during 2002 in the CESA-1 tower facility at Plataforma Solar de Almeria (PSA) in Spain. The main goals of the project were to develop a solar receiver cluster able to provide pressurized air of 1000 degrees C and solve the problems arising from the coupling of the receivers with a conventional gas turbine to demonstrate the operability of the system. The test set-up consists of the heliostat field of the CESA-1 facility providing the concentrated solar power, a pressurized solar receiver cluster of three modules of 400 kWth each which convert the solar power into heat, and a modified helicopter engine (OST3) with a generator coupled to the grid. The first test phase at PSA started in December 2002 with the goal to reach a temperature level of 800 degrees C at the combustor air inlet by the integration of solar energy. This objective was achieved by the end of this test phase in March 2003, and the system could be operated at 230 kWe power to grid without major problems. In the second test phase from June 2003 to August 2003 the temperature level was increased to almost 1000 degrees C. The paper describes the system configuration, the component efficiencies and the operation experiences of the first 100 h of solar operation of this very successful first test of a solar operated Brayton gas turbine system. (c) 2005 Elsevier Ltd. All rights reserved.