the experimental study (bmft fb t 79-143) had shown essential possibilities for cost reduction of photovoltaic power supply systems which could open up a larger field of application. this had been the reason for the definition of an 8-year-program. its first phase is finished. the following development activities have been carried out: replacement of single crystalline by multicrystalline silicon, development of production processes for solar cells and solar generators using low-cost alternative materials; development and construction of experimental production lines with larger capacity for optimization of processes and production of higher quantities of prototype solar cells and solar generators. development and production of power conditioning equipment, design of complete photovoltaic energy supply systems and test of all components in world-wide field tests. it has been proven that by realizing these development steps the production costs could be decreased by the factor of 10. encouraged by this success a follow-on program has been planned which gives rise to expecting further important cost reductions for photovoltaic power supply systems. (era citation 09: 025671)