To attain an ongoing electricity economy, developing novel widespread electricity supply systems based on diverse energy resources are critically important. Several photovoltaic (PV) technologies exist, which cause various pathways to produce electricity from solar energy. This paper evaluates the competition between three influential solar technologies based on photovoltaic technique to find the optimal pathways for satisfying the electricity demand: (1) multicrystalline silicon; (2) copper, indium, gallium, and selenium (CIGS); and (3) multijunction. Besides the technical factors, there are other effective parameters such as cost, operability, feasibility, and capacity that should be considered when assessing the different pathways as optimal and viable long-term alternatives. To aid this decision-making process, a generic optimization-based model was developed for the long-range energy planning and design of future electricity supply system from solar energy. By applying dynamic programming techniques, the model is capable of identifying the optimal investment strategies and integrated supply system configurations from the many alternatives. The features and capabilities of the model were shown through application to Iran as a case study.