The main objective of the proposed work is to prepare the PV market for the introduction of the novel high efficiency and low cost polycrystalline thin film technology (CIS and CdTe) which will enter the market from European production towards the end of year 2000. For a successful market implementation a thorough investigation of the outdoor performance is essential. A warning example has been the market launch of amorphous silicon that suffered from insufficient field experience before the worldwide introduction of the technology. The project evaluates the field performance of CIS and CdTe modules at test sites in Northern, Central and Southern Europe, develops a model to calculate the energy output for any sites and climates, supplies feedback to the manufacturers (including results from accelerated outdoor ageing) to develop an improved module generation and -after a second test phase- gives an assessment of the technology.