If you approve your facility's power bills, there is a fair chance one of the line items has never been explained to anybody in the building. Depending on the utility it says power factor, or reactive demand, or something close. It arrives every billing cycle. We have walked into facilities that had been paying it for ten years without anyone knowing what it was.
Why nobody catches it
- The invoice gets approved on schedule, the way invoices do.
- Nobody actually owns reading it line by line.
- In any single month it's small enough to clear review without a question.
- There's no alarm and no outage attached to it. Nothing breaks, so nothing prompts anyone to look.
- Electricity gets filed under fixed overhead rather than something you can change.
Small monthly, large annually
Small enough each month to skip past, big enough over a year to matter. Most facilities find it by accident: an energy audit, a new controller going in, somebody in accounting asking a question on a quiet afternoon. By then it has usually been running a year or more.
What makes it worth chasing is that the money buys you nothing. No production, no protection, no equipment.
So what's the charge for?
Reactive power. Your facility draws it, the utility has to supply it, and past a certain point they bill you for the privilege.
Power factor is the ratio between the real power your facility puts to work and the total it pulls off the system. Induction motors running lightly loaded, older lighting ballasts, welders and some variable frequency drives all draw reactive current that does no useful work but still has to be generated, carried and accounted for. Most utilities set a threshold, commonly 0.90 or 0.95, and apply a penalty or a separate reactive demand charge below it.
This is not a billing error and there is nothing to argue about with the utility. The charge runs as long as the condition behind it does.
Why we'd chase this one before the others
Most electrical spending has to be justified on risk, which means asking somebody to put money against something that might happen. This one is already on the bill in black and white. Correction is well understood engineering and the payback is arithmetic you can hand to a CFO without a caveat attached to it.