Kvarh

[00071]

can any one tell me how to calculate the cost charge/kvarh.

i have a 10mw power plant, the cost charge/kwh is N22,50, how can i calculate the cost/kvarh, the reactive energy

 

[davidbeach]

You look at the utility rate schedule that applies.

 

[Skogsgurra]

A clarification.

You may have expected some kind of physical relationship between cost for kWh and kvarh. But there is none, since utilities apply widely differing pricing for active and reactive "energy".

Your utility (or knowing neighbour) can help you answer this question.

Gunnar Englund

http://www.gke.org

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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

 

[00071]

thank you all, but am suppose to come up with the cost for kvarh for my organization, what i want to know are the factors or basis to arrive at a particular cost, we cannot just charge arbitrarily, there must be a basis at which we must arrive at a given cost, house please help out. thanks

 

[davidbeach]

But kVArh charges are arbitrary. Just look at all the variation.

 

[waross]

The more conservative charges will pay for correction capacitors in about 8 to 18 months. Some charges are more onerous.
Looking at it another way, The cost of equipment depends more on KVA than on kW.
A 100 KVA transformer will supply
100 kW at 100% power factor,
75 KVA at 75% power factor, etc.
You may want to consider the extra capital cost of larger equipment to service the extra KVA resulting from a power factor less than unity.
There are several ways to consider the power factor.
1> Monthly average.
2> Peak power factor.
3> Power factor at maximum KVA load. (I would tend to go with this one.)
4> Power factor at peak kW load.
I hope this helps.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[Bronzeado]

Hi folks,

Has anybody thought in charging "energy" based on kVAh?

Regards,

Herivelto

 

[Skogsgurra]

Hello Herivelto!

Always interesting with new thoughts. The idea of charging kVAh is worth some consideration. Honestly, I do not know where my discussion below will end :-(

The reason why utilities are charging kWh is because every kWh corresponds to a certain amount of coal, oil, water, uranium or what have you. So there is a direct and measurable relation between kWh and the fuel used.

The reason why they (often - and usually very differently) charge kvarh is that kvar heats generators, transmission lines, transformers and switchgear so that you need more and bigger of everything to transmit a certain amount of power. Or, reverse, the amount of power that can be transmitted is reduced when kvars are high.

If you charge kVAh, you could have any load connected and the cost would practically only depend on RMS current drawn from the line (constant line voltage assumed). With today's non-linear loads, that would mean that the utility has to build transmission lines that can deliver perhaps twice the actual RMS current that they get paid for while a customer that has a well-compensated and linear load (PF close to unity and sine formed currents) only pays for actual energy plus some losses.

If you compare this with the situation where kWh and kvarh are charged separately, I think that the kVAh scenario is the worse scenario. It leaves the utility partly uncompensated for overusage of their equipment and it does not encourage the customers to install "green" equipment.

So, I guess that your idea - new and interesting as it may be - ends up on in the scrap-yard together with some other new and interesting ideas that didn't really make it to the Nobel Prize

Gunnar Englund

http://www.gke.org

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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

 

[Bronzeado]

Thanks Gunnar for your words. Lets worm up the discussion!

I would say that the "energy" today is charged including some "factors" to try customers use it better.

So, if we agree in changing the BASE of the UNIT from kWh or kvarh to only kVAh, initially we could change the "factors" proportionally.

For non-linear or distubing loads, new "factors" including distortions, imbalances, fluctuations, etc. of the customer currents could be used. At the end of the day, the "energy" would be charged as kVAh x Quality Factor.

This Quality Factor (QF) should be discussed and defined as a basket of all "factors" used today plus the new "factors" regarding the quality of the current/voltage (energy) used/delivered.

This may be a dream, but if we dream together it may become a reality!

Best regards,

Herivelto

 

[slavag]

Hi Herivelto.
I don't know about change from kWh to kVAh charge.
This is some revolution.
But additional QF, for my pinion, we must add today and urgently.
Best Regards.
Slava

 

[Skogsgurra]

The QF already exists, at least to some extent, in the K Factor used to select transformer material and winding techniques. But, the K Factor does not include displacement power factor, the cos(phi1). Hervielto's QF should include the two.

Maybe, there is already a committee discussing this out there?

Gunnar Englund

http://www.gke.org

--------------------------------------
100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

 

[waross]

The present practice of charging for energy used, and adding a penalty for inefficient use (p0or power factor) is perhaps the fairest most accurate way to charge.
A charge based on KVAh will probably be unfair to someone.
I have always viewed the penalties for VAR usage as an incentive to correct the power factor. No one has to pay penalties.
however, charging for KVAHrs may be just another way of penalizing a poor power factor. Any one would still have the option to correct his power factor.
An added bonus for the utility would be that such a charge may obscure the fact that basically poor power factor isbeing penalized. Perhaps fewer customers would correct their power factor. Given that many power factor penalties are intended to motivate customers to correct their power factor and are quite onerous, utility revenue may be increased when power factor penalties are made less recognizable on the power bill.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[TurbineGen]

Am I correct in assuming 00071 is only concerned with the generation component and not with the transmission of his power? In that case, your billing should be directly porportional to the amount of fuel and upkeep required to supply power whether that means chargeing for kWh and penalizing for power factor or charging for kVAh.



Charging a base number per KVARh in my opinion makes little sense. Your prime mover is capable of 10 MVA, correct? If a customer uses only 1 MVAR you can still generate at 10 MW (more or less). However if a customer uses 7 MVAR, you can only generate 7 MW. Same with 6 MVAR and 8 MW. As MVAR increases, your MW capability drops exponentially. This is why power utilities charge a base per MW and add a penalty for power factor.

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If it is broken, fix it. If it isn't broken, I'll soon fix that.