From Techno-Economic Optimization to Implementable Low-Carbon Residential PV Systems Using an Integrated Rooftop, Grid, and Decarbonization Framework

Techno-economic optimization of residential photovoltaic (PV) systems often yields continuous capacities that are not directly buildable. This study develops an integrated framework linking techno-economic sizing, discrete component selection, rooftop geometry, low-voltage grid interconnection, and screening-level decarbonization. Three residential targets previously obtained with HOMER Pro (0.460, 1.310, and 3.890 kW) at 4.45 MXN/kWh were translated into commercial configurations. Evaluation of 430–460 W modules and compatible microinverters selected a 435 W module and IQ8A architecture, producing 1-, 3-, and 9-module systems of 0.435, 1.305, and 3.915 kWp with a mean absolute sizing deviation of 2.15%. At a 16° tilt, the minimum inter-row spacing was 0.817 m, with reserved rooftop areas of 6.754, 13.433, and 36.770 m2. Hourly PVGIS-ERA5 simulations (2019–2023), accounting for temperature, electrical losses, inter-row shading, and microinverter clipping, yielded mean annual AC generation of 855.32, 2565.95, and 7688.61 kWh, respectively. The corresponding annual clipping losses were 4.50, 13.50, and 40.51 kWh. Using the official 2024 Mexican grid emission factor of 0.444 tCO2e/MWh, the estimated avoided operational emissions were 0.380, 1.139, and 3.414 tCO2e/year, respectively. The framework links optimization to implementable residential PV designs, complemented by independent economic screening and illustrative point-of-connection voltage-rise analysis, both subject to site-specific validation.