The use of fossil-based energy resources as primary energy sources to meet rising energy demands reveals economic, environmental and social problems at a global scale. Solar energy is the most important renewable energy source as an alternative to fossil energy sources. As with all renewable energy systems, solar energy facilities also have a high initial cost and low operating costs. Therefore, solar energy investments with a high initial cost necessitate a sensitive and accurate decision. Environmental and social factors, as well as technical and economic factors, have an essential influence in choosing the right site for solar energy plant projects. The hesitant Pythagorean fuzzy TOPSIS method is applied to select the most suitable plant among the alternative solar power plant projects with different environmental and social characteristics in the Pythagorean fuzzy ambient. The TOPSIS method, based on the Pythagorean fuzzy set theory, provides a more realistic solution to decision-making problems in the Pythagorean fuzzy environment.