Abstract.

This study addresses the underperformance of photovoltaic solar plants in Colombia’s Engineering Construction & Procurement (EPC) contracts, identifying causes and proposing solutions. Simulations of operational and pre-operational plants revealed that performance expectations depend on the meteorological databases used, with significant differences between on-site measured data and satellite image-based data. An evaluation of the Performance Ratio (PR) and weather-corrected PR showed decreased performance with on-site data and increased variables like module temperature and irradiance. The study highlights the inadequacy of the TMY PR metric in capturing curtailment and clipping phenomena, observing discrepancies of up to 10% when evaluated with on-site data. To address these nonlinear behaviors, the research suggests incorporating a new methodology for calculating the guaranteed PR which is calculated by sub-hourly on site data simulation for the periods where the saturation of the plant is bigger than the expected with the reference TMY simulation.

The proposed methodology emphasizes using the PR under the conditions for which it is valid and correctly represents the non-linear conditions to which the plant to be evaluated is exposed in reality. This approach aims to improve performance evaluation practices, ensuring accurate and fair assessments, and maintaining transparency and trust among all parties in EPC contracts.