Currently, renewable energy projects are growing, and one of the critical unforeseen consequences that has emerged is curtailment. This study focuses on characterizing a full dataset of real operational curtailed electricity from wind energy projects in one-hour time steps, obtained through Supervisory Control and Data Acquisition over the years 2022 and 2025 of operation in Chile. The case study is based on the national electrical system of Chile, and the analysis incorporates both curtailment patterns and more significant features. These results can ultimately be used as an input source for annexed projects, such as energy storage systems or green hydrogen production. The total installed capacity increased from 3.0 GW to 5.0 GW during this period, representing a 66% expansion, while energy generation increased by only 22%. Curtailed energy increased from 7% to 13% of total potential output, equivalent to approximately 3.4 TWh of unused clean energy. Location analysis reveals that around 60% of generation and curtailment occur in northern Chile, where grid congestion is most pronounced. Monthly trends show a pattern that combines a linear upward increase associated with growth in installed capacity and a cyclical seasonal component driven by resource variability. These findings highlight that curtailment has become a structural limitation for renewable integration, primarily due to insufficient transmission expansion and system flexibility.

Bismuth oxychloride (BiOCl)– copper oxide (CuO) heterostructures were synthesized via a solvothermal route and assessed as visible-light-driven photocatalysts for methyl orange (MO) degradation. Different CuO loadings deposited on BiOCl microspheres were investigated to identify the optimal composition. Structural and physicochemical characterization revealed that low CuO content (0.6 wt. %) promoted uniform dispersion and enhanced surface area, whereas higher loadings led to nonuniform coverage and reduced photocatalytic efficiency. Operating conditions were optimized using response surface methodology based on a central composite design, considering catalyst dosage (0.1–0.8 g L⁻¹) and pH (4–9). The highest degradation efficiency (~50% after 60 min irradiation) was achieved at pH = 4 and a catalyst dosage of 0.8 g L⁻¹ using the BiOCl surface modified with 0.6% CuO. Kinetic analysis followed a pseudo-first-order model. Mass spectrometry identified transient intermediates associated with demethylation and desulfonation pathways, while radical scavenger experiments confirmed hydroxyl radicals (^•OH) as the dominant oxidizing species, with a secondary contribution from superoxide radicals (^•O₂⁻). These results highlight the critical role of CuO dispersion and interfacial quality in enhancing charge separation and photocatalytic performance, providing practical guidelines for the rational design of BiOX-CuO heterostructures for water remediation applications.