Solar, storage and hybrid plants for industry, with the switchboards built in our own works.
Free tool for industrial plants
Power factor and APFC sizing calculator
Enter your average load and the power factor on your bill. See the capacitor bank needed to reach your target, how much billed kVA falls as a result, the penalty you stop paying or the incentive you start earning, the indicative APFC panel cost and the payback. Runs in your browser; nothing is uploaded.
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Your numbers
Enter the average load and the present power factor to begin.
—capacitor bank to reach target
—billed kVA reduction
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The headline numbers are free. The full breakdown, sizing and payback are emailed to you and unlocked here once you verify your work email.
- Full breakdown of every figure
- System size, capex and payback
- What to do next, flagged by our engineers
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What power factor costs you
Two separate charges
A low power factor costs twice. The DISCOM levies a penalty, usually a percentage of energy charges for every 0.01 below a threshold, and pays an incentive above a higher threshold. Separately, because demand is billed in kVA and not kW, a poor power factor inflates the kVA you are billed for every month. Correction recovers both.
How the bank is sized
The reactive power needed is the load in kW multiplied by the difference between the tangent of the present and the target power factor angles. The calculator rounds up to a standard bank and estimates the drop in apparent power. An APFC panel switches the bank in steps so the target is held as the load changes.
When plain capacitors are the wrong answer
Variable frequency drives, rectifiers and welding sets inject harmonics. A plain capacitor bank can resonate with them, overheat and fail within months. On those sites a detuned APFC with series reactors is specified, which costs more and lasts. Tell the calculator about drive load and it quotes the detuned type.
What power factor should an industrial plant aim for?
Between 0.97 and 0.99 lagging. Above that, the incentive gains are small and over-correction risks a leading power factor, which some DISCOMs also penalise. The target is set in the APFC relay and held automatically.
Why has my power factor fallen recently?
Usually a failed capacitor stage or a contactor that no longer closes, which the APFC relay may not flag. A quick check of the bank's step indication against the relay's demand tells you; the fix is often a single stage, not a new panel.
Does solar or a battery change my power factor?
Inverters and PCS can supply or absorb reactive power on command, so a hybrid plant's EMS can hold your power factor without a separate bank. We account for this when sizing, which sometimes removes the need for an APFC panel altogether.
