Designing an optimal commercial solar array requires a thorough understanding of a facility's electrical load profile. Simply matching annual kilowatt-hour (kWh) totals is often insufficient, because utility billing structures impose distinct charges based on peak demand timing and time-of-use windows.
1. Volumetric Energy (kWh) vs. Peak Demand (kW)
Commercial electric bills are split into volumetric energy charges (kWh) and peak demand charges (kW). Peak demand charges are calculated based on the single highest 15-minute power spike during a billing cycle. Solar generation reduces kWh consumption, but may require energy storage or demand management strategies to reduce peak kW spikes.
2. Time-of-Use (TOU) Windows
Utilities charge higher rates during afternoon and evening peak hours. Understanding when your facility consumes electricity relative to utility TOU periods helps ensure solar array sizing matches high-cost rate windows.
3. Seasonal Variation Analysis
Analyzing 12–24 months of billing data accounts for summer air-conditioning spikes or winter heating loads, preventing over-building array capacity based on a single high-usage month.