This tool was developed by the Gulf Coast Center of Excellence for use on energy assessments and is free to download.
Inputs:
- Current power factor (found on utility bills)
- Current billed demand (found on utility bills)
- Client desired power factor
- Utility mandated minimum power factor (provided by utility company)
- Avoided cost of electrical demand
- Costs of adding fixed and variable capacitance (per KVAR)
Outputs:
- Annual cost savings
- Minimum and maximum amount of capacitance needed
- Implementation cost
- Simple payback period
Tool preview:
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Tool for electricity bills that are charged based off of kilowatts (kW):
Tool for electricity bills that are charged based off of kilovolt-amps (kVA):
What is a Power Factor?
Simply put, a power factor is a ratio between two types of power:
1) The “usable” or “real” power, PR, is measured in kilowatts (kW). This power is what motors in the facility need to do work or spin.
2) The “apparent” power, PA, which is measured in kilovolt-amperes (kVA). This power represents not only the real power used to spin motors, but the reactive power used to energize motor magnetic and electric fields as well, so it is greater than the real power.
Though the facility only measures the real power (kW), the utility company has to supply the apparent power (kVA) to the facility. The power factor indicates how much of the power the facility is using in proportion to the amount that the utility is actually supplying. The power factor is equal to the cosine of the angle in the power triangle, shown below.
Often utility companies penalize power factors by assigning extra fees to facilities that have power factors over a certain threshold. If the utility charges the facility based off of apparent power (kVA) instead of real power (kW), the facility is automatically penalized if their power factor is anything less than one.
How can you improve your facility’s power factor?
The way to improve your power factor is to install capacitors in your facility. Capacitors decrease the third leg of the power triangle, the reactive power (kVAR), thus increasing the overall power factor. This results in direct savings due to eliminating the difference between the values of apparent power and real power by actually lowering the billed demand to a value equal to the used demand.