Power Factor Formulas

Here are 8 Types of Power Factor Penalties: Which One Does Your Utility Use?

kVA (Demand) Rate Penalty

What it is: You get charged extra if your PF is below 1.0 (100%). The penalty is applied directly to your apparent power (kVA) demand.

How the penalty works: You pay a fixed fee ($/kVA) for all your measured kVA demand if PF < 1.0. Lower PF means higher kVA for the same real power (kW), leading to a higher charge.

Simple Example: You used 800 kW at 80% PF (so kVA = 1000). Demand charge = $10/kVA. Total Demand Charge = 1000 kVA * $10/kVA = $10,000. (The "penalty" is built-in because you pay for kVA, not kW).

PF (kVA) Adjustment

What it is: If your PF is below a target (e.g., 90%), the utility pretends your minimum demand was higher based on that target PF.

How the penalty works: They calculate a "Billed Demand" = Target PF% Measured kVA. You are then charged your normal demand rate ($/kW or $/kVA) on this higher Billed Demand value.

Simple Example: You used 800 kW at 80% PF (kVA=1000). Target PF=90%. Billed Demand = 90% 1000 kVA = 900 kW. If demand charge is $10/kW, Penalty Charge = (900 kW - 800 kW) $10/kW = $1,000.

PF (kVA) Adjustment

What it is: If your PF is below a target (e.g., 90%), the utility pretends your minimum demand was higher based on that target PF.

How the penalty works: They calculate a "Billed Demand" = Target PF% Measured kVA. You are then charged your normal demand rate ($/kW or $/kVA) on this higher Billed Demand value.

Simple Example: You used 800 kW at 80% PF (kVA=1000). Target PF=90%. Billed Demand = 90% 1000 kVA = 900 kW. If demand charge is $10/kW, Penalty Charge = (900 kW - 800 kW) $10/kW = $1,000.

PF Magnitude (kW Demand) Adjustment

What it is: Your demand charge is increased or decreased by a percentage for every percentage point your PF is below or above specific utility targets.

How the penalty works: For each 1% your PF is below a threshold (e.g., 90%), your net kW demand charge increases by a set % (e.g., 1%). Conversely, for each 1% your PF is above another threshold (e.g., 95%), your charge might decrease.

Simple Example: You used 800 kW at 80% PF. Demand charge = $10/kW. Penalty rule: Increase charge 1% for each 1% PF below 90%. PF is 10% below 90% (90% - 80% = 10%). Penalty Factor = 10%. Penalty Charge = 800 kW $10/kW 10% = $8,000 * 0.10 = $800.

PF Multiplier (PFM)

What it is: The utility uses a special number (Multiplier) from a table or formula based on your PF. This multiplier increases your billed demand.

How the penalty works: Your Billed Demand = Your Actual Demand (kW or kVA) PF Multiplier. You pay your demand charge on this multiplied value. A low PF gives a high multiplier (>1.0).

Simple Example: You used 800 kW at 80% PF. PF Multiplier (from utility) = 1.086. Demand charge = $10/kW. Billed Demand = 800 kW 1.086 = 868.8 kW. Penalty Charge = (868.8 kW - 800 kW) $10/kW = $688. (Or directly: 800 kW $10/kW 0.086 = $688).

kvar Demand Charge

What it is: You get charged extra specifically for the amount of reactive power (kvar) you use above a certain limit relative to your real power (kW).

How the penalty works: The utility sets a maximum allowed kvar (e.g., 50% of your kW demand). You pay a fee ($/kvar) only for the kvar demand exceeding this limit.

Simple Example: You used 800 kW at 80% PF (kvar demand = 600). Limit = 50% of kW = 400 kvar. Excess kvar = 600 kvar - 400 kvar = 200 kvar. Charge = $0.45/kvar. Penalty Charge = 200 kvar $0.45/kvar = $90.

kvarh Charge

What it is: You get charged for the total amount of reactive energy (kvarh) you use over the billing period, similar to how you pay for kWh.

How the penalty works: You pay a set rate ($/kvarh) for every kvarh measured on your meter. There's no specific limit; you pay for all reactive energy used.

Simple Example: Your meter showed 500,000 kvarh used. Charge = $0.000835 / kvarh. Penalty Charge = 500,000 kvarh $0.000835 / kvarh = $417.50.

kWh Adjustment (Based on Adjusted Demand)

What it is: If your demand is adjusted upwards due to a low PF penalty (using methods 2, 3, 4, or 5), this higher demand value is then used to calculate tiers for your energy (kWh) charges, making them more expensive.

How the penalty works: Utility billing uses tiered rates (cheaper per kWh for higher usage blocks). The size of the first blocks is often defined as "X kWh * Demand". If your Demand is increased by a PF penalty, these initial, cheaper blocks become larger, pushing more of your actual kWh usage into higher, more expensive rate tiers.