The project: a commercial rooftop solar-plus-storage system for a mid-size warehouse/distribution facility — 100,000 sq ft roof area, existing 480V three-phase service. Every sizing decision in this series traces back to this facility's actual electricity usage pattern.
A commercial solar-plus-storage project is sized against the facility's actual load profile — interval electricity usage data, typically 15-minute intervals from the utility's smart meter, showing exactly how much power the facility draws hour by hour, day by day, across a full year. This is fundamentally different from residential solar sizing, which is often driven by annual kWh consumption alone; a commercial project like this warehouse cares just as much about the facility's peak demand (the highest 15-minute average kW draw in a billing period) as its total energy use, because commercial utility rates typically include a demand charge — a separate fee based on peak kW, not just total kWh consumed.
For this warehouse/distribution facility, the load profile has a shape typical of the building type: a relatively flat baseline load from lighting, refrigeration (if applicable), and conveyor/material-handling equipment running through operating hours, with demand peaks that often coincide with forklift charging stations or loading-dock equipment cycling on simultaneously. That peak demand — not the average load — is exactly what Step 4's battery sizing targets for demand-charge reduction, and understanding when those peaks occur relative to when the solar array (Step 2) is actually producing is what determines whether solar alone can offset them or whether storage is needed to shift generation to match the peak.
This project's analysis uses a representative annual load profile for a facility of this size and type: roughly 3.2 million kWh of annual consumption, with a peak demand around 850 kW during operating hours. Those two numbers — annual energy and peak demand — are the load profile's two most consequential outputs, and they're what Step 2's PV array sizing and Step 4's battery sizing are both built against.