Off-Grid Hybrid Sizing Checklist (IEC 62548 Compliant)

IEC 62548:2017 specifies requirements for the design of photovoltaic arrays in off-grid applications, emphasizing system-level safety, energy autonomy, and resilience under variable environmental and load conditions. Unlike grid-tied standards (e.g., IEC 62109 or IEC 61215), IEC 62548 explicitly addresses standalone hybrid configurations where energy generation, storage, and dispatch must be co-optimized without utility support. The sizing checklist translates these normative requirements into actionable engineering steps—including irradiance-based PV yield modeling using long-term meteorological data (e.g., NASA SSE or PVGIS), probabilistic load profiling with diversity and peak demand factors, battery depth-of-discharge (DoD) and cycle-life derating, generator runtime optimization to minimize fuel use and wear, and comprehensive loss accounting (wiring, MPPT, inverter, temperature, soiling, aging). Crucially, it mandates verification of fault protection coordination (e.g., overcurrent, DC arc-fault, ground-fault detection), thermal management for battery enclosures, and redundancy planning for critical loads. Practitioners apply the checklist iteratively during conceptual, preliminary, and detailed design phases—and often embed it within digital tools (e.g., HOMER Pro, PVsyst + custom scripts) to automate compliance reporting and sensitivity analysis.