A Methodological Proposal for ENFICC Calculation in SMR under Colombia’s Reliability Charge Scheme under Climatic Stress

This sutdy presents a probabilistic methodology for estimating the firm energy (ENFICC, from the Spanish Energía Firme para el Cargo por Confiabilidad) of small modular reactors (SMRs) in the context of Colombia’s electricity market. In this market, generators receive capacity payments through the Reliability Charge mechanism, which is based on their certified ability to supply firm energy during critical system events. Recognizing the critical role of cooling system configuration in determining a reactor's exposure to climatic stress, the proposed framework introduces a typology of SMRs based on three categories: freshwater-cooled (Group A1), seawater-cooled (Group A2), and non-water-cooled (Group B). For each group, the methodology incorporates stochastic modeling of availability, including scheduled maintenance and SCRAM events, and applies differentiated climatic adjustments. Group A1 includes a monthly hydrological derating factor; Group A2 applies a thermal correction post-simulation; and Group B requires no adjustment due to its climate-resilient cooling design. A Monte Carlo simulation of a 300 MW reference reactor is conducted to quantify the impact of each classification on ENFICC outcomes. Results show clear differentiation across groups, validating the relevance of incorporating environmental dependency into firm energy estimation. The proposed framework supports regulatory adaptation for the inclusion of SMRs in Colombia’s Reliability Charge mechanism and contributes to broader goals of energy security, diversification, and resilience. Limitations and future refinements include the integration of high-resolution environmental data from institutions such as NOAA and IDEAM.