See the demand charge a battery shaves off.
Enter your monthly peak, tariff rate and battery size; the tool reads out the kW it can clip and the demand-charge dollars that frees up.
How demand charges work
Most C&I bills carry two parts: energy (kWh you consume) and demand (your highest sustained kW that month). A single peak — a chiller and a compressor starting together on a hot afternoon — can set the demand charge for the entire billing period. A battery discharges into that window so the meter never sees the full spike.
Peak shaving is the fastest-paying layer for most C&I batteries. For how it fits alongside other value streams, read the peak shaving explainer.
What the tool assumes
- One revenue layer
- Demand-charge reduction only. No energy arbitrage, capacity, frequency revenue, ITC or other tax credits — so this is not a payback or full-ROI number.
- Reliable clipping
- The battery is available and clips the peak every billing period. A single missed month resets that month's charge to the un-shaved peak.
- One sustained window
- The peak is treated as a single block of the duration you enter. Real load shapes with several separate peaks may need more energy to cover all of them.
- Energy vs power limit
- If usable kWh can't hold the battery's kW for the whole window, the sustained shave is capped at usable kWh / window hours — the tool flags this.
Typical demand-charge rates
| Rate | Where it lands |
|---|---|
| $10/kW/mo | Low C&I / smaller utilities |
| $15/kW/mo | Typical secondary-voltage C&I |
| $20/kW/mo | Mainstream US commercial tariff |
| $25/kW/mo | High-demand-charge territory (e.g. parts of CA, NY) |
Rates vary widely by utility and tariff. Read the demand-charge line off an actual bill before trusting a number — the presets above are a US C&I starting range, not a quote.
FAQ
What is a demand charge?
A demand charge bills C&I customers on their highest sustained kW draw in the month, separate from the kWh they use. A single spike can set the charge for the whole billing period.
How does a battery cut a demand charge?
The battery discharges during the site peak, so the meter sees a lower net kW. The reduction in peak kW multiplied by the demand rate is the monthly saving.
Why does my battery only shave part of the peak?
Two limits apply. Power-limited: the battery kW is below the peak kW. Energy-limited: usable kWh is too small to hold that power for the whole peak window, so the sustained shave drops to usable kWh / window hours.
What does this calculator NOT include?
It models demand-charge reduction only. It excludes energy arbitrage, capacity or frequency revenue, the ITC and other tax credits, degradation, efficiency losses and CAPEX, so it is not a payback or full-ROI figure.
Need the battery behind the savings?
Hua Power builds the LFP cabinets and containers that shave C&I peaks. Tell us your peak kW and window and we will spec a system sized to actually hold it.