An Investment Framework for Multi-Energy Complementary System Based on the Pythagorean Fuzzy Prospect-GLDS Model

Multi-Energy Complementary Systems (MECS) are integrated energy systems that incorporate renewable energy sources such as wind and solar power, combined with energy storage and conversion technologies. They aim to enhance energy utilization efficiency and ensure supply stability through synergistic optimization. Scientific investment decision-making is crucial for the low-carbon transition of regional energy systems. However, MECS investments face challenges such as high uncertainties and the fuzziness of expert evaluations. To address this question, this paper proposes a multi-criteria decision-making (MCDM) framework integrated with fuzzy theory. An evaluation system is constructed, which includes five dimensions: resources, economy, environment, society, and infrastructure. The Choquet integral is employed to handle resource indicators, Pythagorean fuzzy sets (PFS) are introduced to process qualitative evaluations, and a combined weighting approach integrating Fuzzy Weighting with Zero-Inconsistency (FWZIC) and Weights by Envelope and Slope (WENSLO) is utilized to determine criteria weights. Finally, prospect theory is fused with the Gained and Lost Dominance Score (GLDS) method for alternative ranking. An empirical study on MECS investment in Hebei Province, China, is conducted. The results indicate that the economic dimension exerts the most significant influence, and the Chengde Weichang project demonstrates the optimal comprehensive benefits. This research provides methodological references and a practical basis for MECS investment decision-making and regional energy optimization.