The importance of solar PV as a power technology has rapidly grown in the last years and now it is indisputable that it will play a major role in the future energy scenario. One of the most important factors influencing PV penetration in the electricity mix is its investment cost. This cost decreased quite regularly in the past and this trend is expected to continue in the next decades. However, substantial uncertainty still remains on the actual future cost evolution and on the consequent impacts on PV diffusion. Basing on this consideration, a modeling scenario exercise has been set up which aims at exploring the impacts of the different cost patterns on PV penetration in the electricity mix and on other relevant variables. The objective of the exercise is twofold: - From a policy-relevancy perspective, explore different scenarios related to the possible future cost patterns of the solar PV technology; -From a modeling perspective, assess the responsiveness of models to changes in the cost data input. This extended abstract briefly describes the exercise and some illustrative results from the preliminary set of runs.