Power Factor Improvement Saving Cost

Hi zmun I read your second post after writing my other reply. The answer stays the same but to elaborate a bit further. If you are not at present being penalized by your electrical supply company then improving your power factor will return ZERO dollars from your electrical account. Your Kw consumption remains the same. Power authorities measure and charge for Kilowatts not KVA improving your power factor improves the KVA and brings it closer to the Kw as long as you are being charged for Killowatts you electrical bill will not change no matter how much you spend on power factor improvment. Despite what others have said here ther is NO $$ saving to be made on improving your Power Factor unless you are being penalized.

I agree with the zero net savings in costs from measured power usage.

The PF will not change the energy measured. There will however be reductions in the kVAR and the kVARhrs recorded due to an improved PF. This would be one potential source of saving, but only if it is measured and there is a charge from the utility for these.

There are also equipment maintenance improvements, reduced heat losses and some improvements to performance and efficiency.

Not to take away from the basic excellence of "ZERO" as the answer as the question was asked, but it should be clarified that power authorities measure and charge for kiloWatthours mainly, then possibly have charges for kiloWatts, kiloVARhours and kiloVARs etc., depending on the size of the installation.

A nod to VI for the concept of how to evaluate the savings when there are some, however as asked and then clarified, no improvement will be noted in kW or kWh by improving power factor.

Very good answer by V.I

Another item to be added in the calculation is that some utiities have a maximum Demand charge , in most cases calculated obver a 15 min period.

The highest recorded maximum demand is charged for the entire billing period.

Correcting the power factor will result in a lower maximum demand change.

To complicate things even more , you may have a different off-peak billing rate.

So your savings will be diffeent for on and off peak

Hi Guest,

Yes you are right .I do agree with your point.

First of all you must know that there are two types of tariff use in industry

1- Maximum Demand Tarif

2- Energy Tariff

In maximum demand tarif the maximum demand KVA of consumer multiply by fix charges

In Energy traif :

Max. Demand Charges per KVA x Max. Demand KVA of Consumer + Energy Charges per KWH x Energy consumed by user

So first of all you find the max demand charges at 0.75 power factor and which tarif use in your industry put the value according to tarif and find the charges of electricity in case of 0.75 P.F.

After it you calculate max. demand KVA charges 0.95 power factor and which tarif use in your industry put the value according to tarif and find the charges of electricity consumed by you in case of 0.95 P.F. and use following equation for saving cost

charges@0.75P.F - charges@0.95 P.F

in case of 0.95 P.F Max. demand KVA decreased and charges of electricity must be less than 0.75 PF Charges

For more information

cell:+923134440411

Email: peesconsult@hotmail.com

PEES, I am not familiar with a tariff based on power factor since PF is not measured by the utilities.

Demand is usually measured as kW, and would not change as a feature of PF correction.

The kiloWatthour usage would not change by PF correction. The load will still require and use the same energy to operate.

In the example values suggested by the questioner (1mW) the values would however be large enough to measure the kVARhours in addition to the kiloWatthours however, and then power factor and the kVA values can then be dealt with through stated formulae and related tariff charges. Since PF and kVA vary widely in most electrical systems in the short term, it is best to deal with them as max values or average values over a longer period. Correction when indicated for power factor therefore is a bit more complicated to evaluate as VI noted above, and requires a more detailed set of measurements than can be handled in a simple formula as requested.

Dear CJMcGill I want to understand that the KW are not vary during changing power factor I mean to say that when Vlaue of PF change then the value of KW not change the effect of power factor only on KVA or KVAR when power factor increase then value of KVA decrease as well as when PF value increase then the value of KVAR also decrease due to it the electric supply compnies use the tarif i describe above in the industry. if they use use domstic tarif mean KWH tarif in this case the there is no change in KWH due to it user don't correct his power factor then how electric supply compny charge extra charges for low power factor . so first of all we know to usder stand that which tarif is use in the industry and then we analyze the cost of saving

Hey PEES sorry for the delay in response, I was away for a bit.

To clarify my concern with your advise, I worked 23 years in Utility metering dept, field work and management (4,000,000 meters in territory), and never came across a situation that could be calculated as you have described.

kVA is a momentary value, similar to the speedometer of an automobile, and is not metered. This makes for difficulty applying your formulas as given.

Question suggested 1mW, with load running 24/7, = not domestic.

Large commercial services meter kWh, and capture max kW for each period. Along with that the kVARh is metered. From these metered values formulas can be applied (none of the formulas in this thread are valid so far, not to criticize, but so we may give accurate response) which formulae generalize the average PF by educated guess and the experience of the Utility. If perfection were possible, and the load stayed right at 1mW for 24hrs and 30 days, and kVA were metered, then the formulas above might reveal an accurate answer.

kVA is not measured. Modern electronic meters that have displays in kVA values are displaying a calculated, momentary value not a metered value.

Since PF can vary widely during usage of a real load, whatever corrections are used must be tailored to specific circumstances, and be varied along with the changes in order to be effective. The effectiveness will be metered in kVARh, not a momentary value, and compared to kWh for a set period.

I notice a lot of confusion about MAX kW on the forum.

When teaching 'max kW' to students I use an illustration of giving the keys to your teenager for his date and instructing him to drive responsibly. He is not aware that you have noted the odometer reading and rigged the speedometer to go up, but not come down. This way when you check the value of the 'stuck' speedometer the next morning, you will see his 'max MPH' (compares to max kW)'. A look at the odometer will give you how far he drove (compares to kWh). Even though he drove slowly most of the night, it is that speed contest he got suckered into that will earn him a discussion about your max MPH tariff.

Hope this is helpful to our student guest and his question.

Basic answer is that if your utility company is not penalising you for a low power factor at present then the savings are nil

Agree with VI

Further to add to that if electricity board is charging on KVAH then only some savings would be there for improving P.F. keeping in mind other factors as capacitor bank cost, power consumption etc. Penalty is being imposed for poor power factor.