Utility charge for low power factor

[CanuckEngineer]

Hello guys,

I am interested in getting your feedback and your experiences on how your Local Distrubtion Companies, LDC's, charge customers on low power factor.

In particular customers of business and industrial buildings.

For ex: Are your utilities structured so that if you improve your power factor through the use of a Power Factor Correction Capacitor system to above let us say 0.98, that the kVA charge is dropped?, i.e. $0.

The utility up here in Toronto, Canada continue to charge for power factor all the way up to 0.99. I do not understand why? There is barely any reactive load there to charge on, yet they do.

Thanks for the input.

Regards,

RK.

 

[LionelHutz]

All the examples I have seen recently involved a power factor penalty that was built into the demand charges. Basically, the demand was billed on the kW demand or 90% of the kVA demand, whichever was larger.

If you are talking Toronto Hydro then it does appear they charge a bunch of items based solely on kVA which means any power factor other than 1.0 is penalized. But then they also have what appears to be customer gouging charges that use peak kW and max kW instead of the typical demand kW.

 

[CanuckEngineer]

Thanks Lionel.

Quick question:

What is the basic difference between peak KW, max kW and demand kW. I actually thought all three of these were the same, i.e. the highest point of kW occurred throughout the month.

Also, in theory, if the customer improved their power factor to 1.0 or let us say 0.9999, would you think all of those kVA charges should be reduced to 0.

 

[LionelHutz]

#1 - The demand is the average kW over a fixed measuring window, often 15 minutes or 30 minutes. Short events like a motor starting have very little effect due to this averaging. On the other hand, the peak kVA inplies they measure the peak value that was hit. A short event like a motor starting would then be captured. I would think the max would be the same as the peak yet they call it out differently so it must not be the same. You will also notice that they don't indicate demand/max/peak kVA either so that value is not really clear either. Since the utility does not define on their web site these you need to get someone who knows to tell you what they actually use.

#2 - No, the kVA will become the same as KW when the power factor is 1.

 

[DRWeig]

Demand kW is most often averaged over a sliding 15- to 30-minute window.

Peak is instantaneous in most contaexts, and maximum is usually used same as peak.

My experience is the same as Lionel's. Actual demand kW or 90% of demand kVA. Some places it's 85%, some are more.

Good on ya,

Goober Dave

 

[tinfoil]

@OP:

Toronto Hydro, like every other distribution utility in Ontario, pays for ITS monthly peak demand based on the maximum 15-minute demand at the wholesale delivery point, MEASURED IN KVA, NOT KW.

After performing some terrifyingly complex regulatory cost-of-service analyses, this 'volumetric' (based on kVA as the unit) cost is passed on to the demand-based customers.

The consumption is simply measurede in kWhr.

This is a mandated by the regulator (OEB)

 

[jraef]

I do not understand why?

Because they can...

"If I had eight hours to chop down a tree, I'd spend six sharpening my axe." -- Abraham Lincoln
For the best use of Eng-Tips, please click here -> faq731-376

 

[EEIre]

Ireland:

kVARh in excess of one third of total kWh E0.00628