A novel Pythagorean fuzzy-SWARA-TOPSIS framework for evaluating the EU progress towards sustainable energy development.

Energy Union aims to provide clean, secure, and affordable energy for many customers leading societies towards sustainable energy development. Several criteria were introduced in this vein to evaluate the twenty-third EU countries' progress towards energy union goals. The present study proposed and applied a SWARA-TOPSIS framework based on Pythagorean fuzzy sets to rank the EU members considering their sustainable energy development progress. Ten experts working in various fields were selected to support the identified criteria, and a sensitivity analysis based on twenty scenarios was performed to evaluate the proposed model's sensitivity to weight changes. The obtained results indicated that "energy affordability" is the most influential criterion for evaluating countries, and the proposed model is sensitive to weight changes. Luxembourg is also the first-ranked country, followed by Denmark and Sweden, while Bulgaria achieved the worst rank among the EU considering its progress towards the energy union goals. The analysis of the results indicates room for improvement in implementation with the European Union goals by the EU members and the need to consider energy justice and affordability in the policy development, especially in the new members of the EU.