This paper reports on an ongoing model-based field study attempting to answer the following research questions: What are the mental models of participants in the photovoltaic industry? How widely are mental models shared among participants? The mental models of system participants are important because participants are the people with the greatest knowledge about the system, because in any policy solution they are the critical actors, and because it is their decisions and actions from which the behavior of the system emerges. Fifteen experts have so far been interviewed. The knowledge they conveyed was expressed as a set system dynamics models; these models were characterized and compared. The informants all expressed dynamic growth as a result of reinforcing feedback processes, but few perceived of any balancing feedback. Their beliefs indicate successful policies will have to recognize the difference between global and local market effects.