Economic–Operational Assessment of the Spanish Power Market: A Monthly TOPSIS Approach with Endogenous Weights
Daiane R. Santos(1), Jose Maria Yusta(2), Tuany Barcellos(3), Natalia Naval(2) 1. Department of Economics, UERJ (Brasil) 2. Department of Electrical Engineering. E.I.N.A. University of Zaragoza. Spain 3 Estácio de Sá University; PUC-Rio; UNIRIO, Brazil, 2026-06-27

Abstract

The study examines how high levels of renewable penetration shape the economic and operational performance of the Spanish power system. It develops a monthly multicriteria index using the TOPSIS–CRITIC framework and evaluates two viewpoints. The demand perspective values tariff moderation and price stability, while the generator perspective focuses on value capture and revenue recovery. Both perspectives rely on the same data and weights; they diverge only in how each criterion is classified as a benefit or a cost. This structure sharpens the contrast between affordability for consumers and economic viability for producers. The 2025 results reveal high renewable participation alongside persistent intraday volatility and marked swings in economic margins. Winter exhibits positive average margins and a modest share of energy priced below LCOE. From March to May, margins turn negative and nearly all renewable energy trades below LCOE, reflecting abundant supply and depressed prices. Price-level variables add limited explanatory power, whereas volatility, penalized energy, and hourly alignment (ICPG) drive most of the variation in index values. System performance, therefore, does not follow a simple seasonal pattern; it reflects specific interactions between market signals and the evolving mix of renewable technologies.

Key words: Renewable Energy Markets, TOPSIS–CRITIC, Capture Price Dynamics, Solar-Wind Integration.

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