The purpose of this study is to develop a decision model for selecting solar farms. A MCDM model is proposed for the selection of a solar power plant site based on economic, technical, environmental, and sociopolitical criteria which contain 20 sub-criteria. For the purpose of determining the weights of the sub-criteria, the model utilizes the Relative Importance Index (RII) method. A four-stage procedure has been followed for this study, which involves the identification of criteria, the development of a questionnaire (survey), a confirmation factor analysis, the assessment of the degree of importance of criteria, and the ranking of alternative options using gray analysis in a fuzzy environment. An alternate site for a solar power plant is generated using Plackett-Burman Design and these alternatives are evaluated based on Grey Relation Analysis (GRA) and Grey Relation Projection (GRP) in a fuzzy environment.