Background/Objectives: This paper presents a bi-objective mathematical programming model for sizing hybrid renewable energy systems (HRESs) in isolated mini-grids and compares the optimized solutions with the first-year operation of a real system deployed in La Miel, Panama. Methods: The model minimizes the levelized cost of energy (LCOE) and the expected energy not served (EENS), using an ε-constraint approach over a one-year time series (8760 h) of measured demand. For La Miel, the annual demand is 132,578 kWh with a peak load of 28.4 kW. Four configurations are evaluated: (A) diesel-only, (B) photovoltaic (PV)+diesel, (C) PV+batteries, and (D) PV+diesel+batteries. The results are compared with the installed plant (E) including 107 kWp PV, a 40 kVA diesel generator, and lead-acid battery banks (4560 Ah nominal capacity). Results: The optimized hybrid configuration (D) achieves near-zero EENS with an LCOE of 41.4–41.8 cts-USD/kWh, compared to 56.6 cts-USD/kWh for diesel-only. The real system achieves EENS = 0% with LCOE = 48.3 cts-USD/kWh and an annual renewable penetration of 53.2% (up to 68.4% in March 2020), while the optimized case reaches 79.6% on average (up to 95.3% in March). Conclusions: The distinctive contribution of the study is the direct ex ante versus ex post comparison between optimized planning outcomes and the documented first-year operation of the installed system. Operational constraints observed on site (e.g., minimum battery SoC of 60% to comply with voltage quality limits) and demand growth explain part of the LCOE gap between optimized and real performance.
Valdés-Bosquez et al. (Fri,) studied this question.