Business
Commercial Demand Charge Calculator
Estimate energy use, energy charges, fixed charges, baseline savings, and simple payback while keeping peak-demand exposure explicit.
Monthly demand charge-
Monthly energy charge-
Monthly utility subtotal-
Monthly total after surcharge-
Target reduced peak demand-
Monthly demand-charge savings-
Annual demand-charge savings-
Simple project payback-
Demand charge share of subtotal-
Decision view
Daily facility load profile and peak-demand marker
Daily facility load profile and peak-demand markerOperating hours and load factor create an explicit daily load shape; the rated peak remains distinct from accumulated monthly kWh and tariff cost.
Peak-demand reduction and project paybackMeasured peak demand is reduced to the entered target while monthly energy, demand-charge savings, implementation cost, and payback remain separate.
Exact scenario comparisonTarget peak-demand reduction (%) changes while all other entered assumptions remain constant.
| Target peak-demand reduction (%) | Monthly demand charge | Monthly energy charge | Monthly utility subtotal | Monthly total after surcharge | Target reduced peak demand | Monthly demand-charge savings | Annual demand-charge savings | Simple project payback | Demand charge share of subtotal |
|---|
Period-by-period detail
commercial electric demand monthly operating projection
How to use Commercial Demand Charge Calculator
- Identify the utility demand interval and ratchet rules.
- Use interval meter data to find coincident peak kW.
- Compare load shifting, sequencing, storage, and efficiency scenarios.
Calculator guide
Understanding Commercial Demand Charge Calculator
Commercial electricity cost can be driven as much by the highest billing-interval kW as by monthly kWh.
Calculation method
How the calculation works
Keep demand in kilowatts separate from energy in kilowatt-hours, calculate each tariff component, and value only the entered peak reduction against the demand rate. Convert equipment power, run time, days, and load factor into kWh, apply the energy tariff, then interpret demand charges as a separate peak-kW layer.
Load profile
Place the billed peak above the daily energy area
The visual separates the hourly load curve, demand interval, billed peak marker, monthly kWh, and tariff cost.
Worked situations
Practical examples
- Two large loads starting together can raise the monthly billed peak.
- Reducing kWh without reducing peak kW may leave demand charges unchanged.
- A ratchet can preserve a prior peak in later bills.
Better inputs
Useful tips
- Analyze interval data rather than monthly totals.
- Separate coincident and noncoincident peaks.
- Check seasonal and time-of-use demand windows.
Before relying on the result
Limitations and common mistakes
- The generic energy inputs do not reproduce every tariff demand rule.
- Ratchets, power factor, coincident peaks, and tiered tariffs are simplified.
- Confirm calculations against the utility tariff.
Reference
Key terms
- Demand interval
- Utility averaging period used to determine billed kW.
- Demand ratchet
- Rule preserving a share of a prior peak.
- Coincident peak
- Loads operating during the same billing interval.
Important note
Calculated from the entered values using the displayed accounting method. Reconcile material decisions with source records and applicable accounting policy.
Frequently asked questions
Can lower kWh leave the demand bill unchanged?
Yes, when peak kW does not fall.
What interval should be used?
Use the interval defined by the utility tariff.
Does this model ratchets?
Not fully.