Due to the increasing awareness of environmental, social and economic factors, solar photovoltaic (PV) system planning requires strategic decision making process for socio-economic development in many countries. The main objective of this paper is to propose a new Multi-Criteria Decision Making (MCDM) approach that is flexible and practical to the decision makers (DMs) in governments for solar PV panel manufacturer evaluation based on qualitative and quantitative factors. Accordingly, a novel two-stage MCDM model integrating Analytic Hierarchy Process (AHP) and Multiplicative Multi-Objective Ratio Analysis (MULTIMOORA) methods under Interval Valued Pythagorean Fuzzy (IVPF) environment is presented, and applied to select the most appropriate solar PV panel manufacturer for solar power plants in Southeastern Anatolia Region of Turkey. As a result, the proposed novel Integrated IVPF-AHP&MULTIMOORA method produces consistent and reasonable results to select the most appropriate solar PV panel manufacturer for the solar power plants in the cities of Southeastern Anatolia Region of Turkey considering some socio-economic sustainable indicators such as cost, environmental, efficiency and technical indices. Furthermore, sensitivity analysis and comparative analysis are also applied to prove the robustness and verification of the results of the proposed approach.