All of the generated renewable energy is guaranteed for system purchase through agreed price feed-in-tariff (FiT). This cost is being reflected to the energy market system costs. A new approach for generation priority or financial settlement procedure can be reduce renewable addition to the system costs. Renewable energy plant (RWEP) approach is defined as an attractive and more sustainable mechanism among the others such as feed-in-tariff (FiT), feed-in-premium (FiP), tax advantages (TA), licence procedure simplification, etc. As for the all investments, finance and sustainability are the most important criteria for RWEP. In this study, return period of solar and wind type RWEP has been calculated and sustainability conditions have been evaluated through different investment and benefit scenarios to increase the understanding of the price level for such an investment compared with the current subsidies. According to the results, USD-cent/kWh 3.5 for solar and USD-cent/kWh 2.5 for wind RWEP FiT reconciliate 5-year return period for average finance models in the frame of some technical assumptions.