Minimum power factor for compensation cost recovery calculator

Minimum power factor to cover annual bank cost is calculated as P / [P/PF_old − C_annual/(M × r_demand)]. Use the stated system boundary and matching input units.

\mathrm{PF}_{\text{min}} = \frac{P}{\frac{P}{\mathrm{PF}_{\text{old}}} - \frac{C_{\text{annual}}}{M \times r_{\text{demand}}}}

Calculator

Enter the values you know and leave one box empty. Calculate finds the empty one, the result or any input.

Worked example

Given

$P$ = 100 kW
$\mathrm{PF}_{\text{old}}$ = 0.75 —
$C_{\text{annual}}$ = 2,400 $/year
$M$ = 12 month/year
$r_{\text{demand}}$ = 12 $/kVA-month

\mathrm{PF}_{\text{min}} = \frac{100}{\frac{100}{0.75} - \frac{2400}{12 \times 12}} \approx 0.8571

Symbols and units

Symbol	Meaning	Unit
$\mathrm{PF}_{\text{min}}$	minimum power factor to cover annual bank cost	—
$P$	unchanged billed real demand	kW
$\mathrm{PF}_{\text{old}}$	initial sinusoidal power factor	—
$C_{\text{annual}}$	annual capacitor ownership and service cost	$/year
$M$	billed months per year	month/year
$r_{\text{demand}}$	monthly apparent-demand price	$/kVA-month

Related calculators

Results are estimates for study and screening. Check the inputs, units and assumptions before you use them for design, billing or contract decisions.