Does Improving Pwr. Factor Lower Bill?

[designer82]

I'm not sure if the Utility charges, let's say an industrial customer, for kW's only or for KVA?

What I'm getting at... If an industrial customer has a very poor power factor and they correct it, will it lower their bill?

If it makes no difference to their elec. bill, then what's the reason facilities spend all that money for PF correction capacitors?


Thanks

 

[Tulsa Electrician]

For the ones that I have worked on, the ansawer is yes.

 

[ptonsparky]

Yes.
Our Ag customers have started to feel the pain of poor PF in the last year or two.

 

[LarryFine]

If they charge for poor PF, then yes. It's energy the infrastructure must be large enough to carry.

At home, where they only charge by the Kwh, no.

 

[drcampbell]

Improving the power factor reduces current, which reduces I2R losses and voltage drop.

 

[Little Bill]

It only lowers the bill the amount they would have been fined for the poor PF had they not corrected it. They don't really take off any of the actual electric bill.

 

[David Castor]

Depends totally on the rate structure they are under. In most cases, there is some type of power factor penalty for commercial/industrial services, although I have found that smaller utilities often don't actually bill for it. Sometimes the pf penalty is somewhat disguised by basing the demand charge on kVA instead of kW. The nature and amount of the pf penalty varies widely. So, the answer should be in their rate schedule ("tariff") and their actual power bill. If there is no pf penalty charge, then the main incentives for adding capacitors would be to free up transformer and system capacity for actual kW loads, raising voltage, and reducing losses (by reducing current).

 

[Sahib]

If there is noticeable voltage drop for an inductive load, a suitable capacitor may be used on the load side to improve voltage and reduce current and thereby line losses.

 

[ron]

Unless the system is loaded to capacity and you need some ampacity headroom, or there is a power factor penalty from the utility, usually the pf correction capacitors are not worth the cost / risk.

 

[kwired]

The biggest savings on your energy bill is usually going to be not paying penalties for having poor power factor.

If you are not charged these penalties you still likely do reduce line losses but those won't normally be significant enough to be that noticeable, especially in light commercial or residential applications.

If you overcorrect you can have a leading instead of a lagging power factor and start to develop similar line losses again.

 

[Jraef]

The biggest savings on your energy bill is usually going to be not paying penalties for having poor power factor.

If you are not charged these penalties you still likely do reduce line losses but those won't normally be significant enough to be that noticeable, especially in light commercial or residential applications.

If you overcorrect you can have a leading instead of a lagging power factor and start to develop similar line losses again.

Yep, the savings is in penalty avoidance. Bottom line, if you do not have a separate kVAR meter in your facility meter setup, then you get no tangible savings benefit from adding PF correction, unless YOU own your distribution service transformers to where YOU pay for the transformer losses.

Forget residential altogether, there is never a penalty. The utility's cost of poor PF from residential loads is baked into the rate we pay, in fact it is not even measured, so correcting it doesn't change your bill at all (although it does help the utility a little tiny bit).

 

[electrofelon]

.

Forget residential altogether, there is never a penalty.

Ballsy move using the word "never" on the MH forum

 

[Sahib]

The biggest savings on your energy bill is usually going to be not paying penalties for having poor power factor.

If you are not charged these penalties you still likely do reduce line losses but those won't normally be significant enough to be that noticeable, especially in light commercial or residential applications.

If you overcorrect you can have a leading instead of a lagging power factor and start to develop similar line losses again.

In plants with large areas such as paper mills, reducing line losses with capacitor connected at long feeders end is cost effective.

 

[ptonsparky]

We installed a communication building for the County 20 years or so ago. The tower had blinking lights that would drop the voltage while on the standby generator. Capacitors where the suggested fix.

 

[Sahib]

We installed a communication building for the County 20 years or so ago. The tower had blinking lights that would drop the voltage while on the standby generator. Capacitors where the suggested fix.

No overvoltage issue for the standby generator then?

 

[ptonsparky]

No overvoltage issue for the standby generator then?

Guessing not. The tower control guys knew what was needed. We didn't install them.

 

[kwired]

In plants with large areas such as paper mills, reducing line losses with capacitor connected at long feeders end is cost effective.

Such plants likely also would be charged penalties for poor PF and would install correction mostly for that reason, at least any North American plant that would likely be the case.

 

[Besoeker3]

In plants with large areas such as paper mills, reducing line losses with capacitor connected at long feeders end is cost effective.

We used unity power factor drives for some of our paper mill drives. These were around 3 MVA 24-pulse drives. No PFC required.

 

[kwired]

We used unity power factor drives for some of our paper mill drives. These were around 3 MVA 24-pulse drives. No PFC required.

When it comes to DC motors or VFD driven AC motors the displacement power factor is pretty much none on the input side of drives, what you have there is mostly distortion power factor.

 

[ptonsparky]

PFC and VFDs make things interesting. We added a single PFC to a project about the time they added quite a few drives. It raised the voltage plant wide. We had POCO change taps, but the older PFC on individual motors still didn't like what was bouncing around. We didn't replace them as they failed. Yes, an EE would have been better.