Turkish government agencies support capital investments in electricity generation from renewable energy sources. When making support decisions related with renewable electrical energy sources, the government agencies should consider various issues such as renewability, cleanliness, origin of the source, supply security, cost per kilowatt hour (kWh), and total electricity generation capacity. The tariff mechanism being used in Turkey provides constant rates per kWh of electricity generated from renewable energy sources. The levels of the rates are determined to stimulate renewable energy sources' usage. In this paper, instead of a constant rate, a feed-in tariff is calculated for each individual electricity generation project using renewable energy source and its level is increased according to the source's desirability with respect to other renewable energy sources. Various criteria are taken into account in determination of electrical energy sources' desirability. Furthermore, a combination of two multi-criteria decision-making (MCDM) approaches (the fuzzy versions of the analytic hierarchy process (AHP) and Technique for Order Preference by Similarity to Ideal Solution (TOPSIS)) is used in obtaining a ranking among alternative renewable electrical energy sources. The developed support model's applicability is illustrated in this paper. The new model developed in this paper has many key benefits. For example, for an individual renewable electrical energy project, final cost per kWh can be calculated and multiplied by new Support Constant to calculate feed-in tariff purchase price per kWh. In another key benefit of the developed model, only local instead of state-wide renewable electrical energy projects can be compared within the AHP-TOPSIS decision hierarchy.