kw and cost

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fayc

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Good morning,
I have a facility that has 7 power centers that I am monitoring with new GE PQMII meters and software.

What I noticed was the lower the kW readings for the day; the higher the cost is for the day.

The higher the kW reading for the day, the lower the cost for the day?

Any thoughts on why shouldn?t it be the other way around?

Thank you

EXAMPLE

Date 3rd shift 1st shift 2nd shift $ Cost


Apr 05 29901.02 60753.06 43088.96 $1,318.28
29kw 60.7kw 43kw


Apr 06 64369.43 98890.59 78426.3 $1,200.09
64kw 98kw 78kw


Apr 07 99208.25 138491.5 114235.3 $1,167.88
99kw 138kw 114kw


Apr 08 134799.5 180155.3 151601.4 $1,163.02
134kw 180kw 151kw
 
I am having trouble as well. A typical bill would have a demand, reactive, and energy charge. The demand would normally be in kW, the reactive in %PF, and the energy in kWh. Sometimes, the demand and reactive are rolled together in kVA. These are dependant on the way the billing is set up with the state public service commissions. :-?
 
That data is from the GE PQMII meter, not from the energy bill. The meter calculates cost if you tell it your $/kWh value.

Also, the meter goes nuts and quits working if you have a single phase outage. I'm on my second one and it already isn't working. It likes to tell me our voltage is over a billion and that we're pulling tens of thousands of amps.
 
drbond24 said:
That data is from the GE PQMII meter, not from the energy bill. The meter calculates cost if you tell it your $/kWh value.

Also, the meter goes nuts and quits working if you have a single phase outage. I'm on my second one and it already isn't working. It likes to tell me our voltage is over a billion and that we're pulling tens of thousands of amps.
Click to expand...
Okay...I had to laugh just reading the second paragraph.

In all seriousness though, we use Square D Power Logic here and due to wiring problems in the control panel I would receive all kinds of weird readings. My problem was related to CT's connected backwards (incorrect polarity) and incorrect phase conductor rotation when connected to the pq meter itself. Our meters are very picky about all of that and I would wager that GE's are too.

I know nothing about GE's product but it could along the same line of "wiring" problems.
 
drbond24 said:
...our voltage is over a billion and that we're pulling tens of thousands of amps.
Click to expand...
Metering the lightning there Ben Franklin? :)

I'm not sure of the rates but down here, electricity is generally most expensive on summer weekdays during the middle of the day. It is cheapest during mild-temperature-season weekends during the night.

It is also cheaper the higher your kWh/kW ratio (i.e. the higher your load factor) and the more kWh/meter point you use.
 
Not to sound rude, but are you sure you don't have one or more of your CTs wired backwards? :)



Edit:
D'oh! didn't fully read bhsrnd's response.

What he said...
 
fayc said:
What I noticed was the lower the kW readings for the day; the higher the cost is for the day.
The higher the kW reading for the day, the lower the cost for the day?
Any thoughts on why shouldn’t it be the other way around?
Click to expand...
If your utility has a rate structure similar to the one I am familiar with for commercial customers, the first block of KWH's are billed at a different rate than the second block of KWH's. The block is dependent on the KW demand. Rate Example:
first 250 KWH's per KW billing capacity is billed at 4.5 cents/kwh. The next block is for KWH's all over 250 KWH's per KW is billed at 2.5 cents per KWH.
For the period in April you show the max demand is 180 kw. As an example,
if you assume that this is the billing demand, then
Block 1 is 250 KWH x 180 KW = 45000 KWH's billed at 4.5 cents per KWH. All KWH's over 45000 kwh's would be billed at 2.5 cents per KWH. A higher KW demand would cause Block 1 to have a higher number of KWH's being billed at the higher rate. The cost for the KW demand is additional.
I am not sure if your measuring device can be programmed to calculate the bill correctly.

Utility Charlie
Are you familiar with this type of billing?
 
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bob said:
If your utility has a rate structure similar to the one I am familiar with for commercial customers, the first block of KWH's are billed at a different rate than the second block of KWH's. The block is dependent on the KW demand. Rate Example:
first 250 KWH's per KW billing capacity is billed at 4.5 cents/kwh. The next block is for KWH's all over 250 KWH's per KW is billed at 2.5 cents per KWH.
For the period in April you show the max demand is 180 kw. As an example,
if you assume that this is the billing demand, then
Block 1 is 250 KWH x 180 KW = 45000 KWH's billed at 4.5 cents per KWH. All KWH's over 45000 kwh's would be billed at 2.5 cents per KWH. A higher KW demand would cause Block 1 to have a higher number of KWH's being billed at the higher rate. The cost for the KW demand is additional.
I am not sure if your measuring device can be programmed to calculate the bill correctly.

Utility Charlie
Are you familiar with this type of billing?
Click to expand...
I believe you have a typo. The "250 KWH x 180 KW = 45000 KWH's" should be "250 h x 180 kW = 45000 kWh"

The rate you are describing is called an hours use of demand (HUD) rate. It is a method of billing based on load factor across a range of kW sizes. It converts the usage into hours, splits the hours into separate billing buckets, then converts each bucket of hours back into kWh for billing. Each bucket has a different price. Sometimes the kWh in the first bucket is further divided into smaller kWh sub-buckets.

The idea is that, on average, there are 730 hours in a month. If you convert the usage into equivalent hours, you can bill based on load factor. The higher the load factor, the higher the HUD. You usually have a declining rate and give a price break for higher load factors. This is because generation is cheaper, on average, for high load factor loads because you can use base load generation plants..

A low load factor customer (1 shift operation, 15-30% LF) would generally have all of their usage billed in the 1st 200 hours bucket. A mid load factor customer (2-shift operation, 30-55% LF) would have some usage in the next bucket as well (200-400 hours). A high load factor customer (3-shift operation or grocery store, over 55% LF) would have usage in the remaining HUD buckets (400-600 and over 600 hours). Usually, only continuous loads like grocery stores, distribution centers, and some manufacturing facilities can reach the 70-80-90% load factor range (511-584-657 hours use of demand)

To convert to HUD you divide the kWh by kW (kWh/kW=h). What this answers is this: If the customer were to start the month using the maximum demand, how many hours would they have to run to use the kWh that were metered? This is why it is called an hours use of demand or HUD rate.

All that being said, I would be surprised if your meter could bill a HUD rate. There are ways to convert the HUD rate into a demand and energy calculation.
 
mivey said:
I believe you have a typo. The "250 KWH x 180 KW = 45000 KWH's" should be "250 h x 180 kW = 45000 kWh"

The rate you are describing is called an hours use of demand (HUD) rate. It is a method of billing based on load factor across a range of kW sizes. It converts the usage into hours, splits the hours into separate billing buckets, then converts each bucket of hours back into kWh for billing. Each bucket has a different price. Sometimes the kWh in the first bucket is further divided into smaller kWh sub-buckets.
Click to expand...

Actually this is not a "TYPO". This is also not a HUD rate. The rate chart
says :
Charge for Billing Capacity:
$5.00 per KW of billing capacity; plus

Charge for Energy:
250 KWH per KW Billing Capacity
4.5 cents per KWH per KW billing Capacity

For all over 250 KWH per KW of billing capacity:
2.5 cents per KWH for all KWH.
Click to expand...
There are rates that have variable billing depending on the utility peak demand period as you have stated. This particular rate is not that type of rate.
 
bob said:
Actually this is not a "TYPO". This is also not a HUD rate. The rate chart
says :
There are rates that have variable billing depending on the utility peak demand period as you have stated. This particular rate is not that type of rate.
Click to expand...
The rate you posted is a HUD rate.

[edit: unless I'm missing what is going on with billing capacity]
[edit: I forgot. There must be a typo (maybe on the rate sheet) because kWh * kW = (kW^2)h NOT kWh. It could be they meant 250 kWh/kW x 180 kW = 45000 kWh]
 
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mivey said:
The rate you posted is a HUD rate.
There must be a typo (maybe on the rate sheet) because kWh * kW = (kW^2)h NOT kWh. It could be they meant 250 kWh/kW x 180 kW = 45000 kWh]
Click to expand...
Thats correct. 250 KWH /KW x 180 KW = 45000 KWH. This represents the
first block of KWH's billed at 4.5 cents. This block can be accumulated
any time during the month with the remainder of the KWH's billed at 2.5 cents
per KWH. With this rate these are the only 2 blocks available. I am aware of the off peak billing. It may be set from say 7 pm to 7 am with a lower rate per KWH. With the new electronic meter I assume that it can be programed
to compute the KWH's during each time period.
 
bob said:
I am aware of the off peak billing. It may be set from say 7 pm to 7 am with a lower rate per KWH. With the new electronic meter I assume that it can be programed
to compute the KWH's during each time period.
Click to expand...
Yes, and even with older meters. They have had peak/off-peak meters for a long time.
 
charlie said:
Yes, this is normally described as billing steps which translates to the more you use, the less you pay for energy. :smile:
Click to expand...
I would say "The more you use, the less you pay per unit of energy". Don't want anyone getting the wrong idea.:D
 
charlie said:
Yes, this is normally described as billing steps which translates to the more you use, the less you pay for energy. :smile:
Click to expand...
But not to be confused with a step rate, where the entire usage amount was billed at a certain rate. The step rates were something like:
If you use less than 1000 kWh/month, you pay 8 cents/kWh
If you use more than 1000 kWh/month, you pay 7 cents/kWh

The next transformation of the step rate was the block rate where the usage was billed in blocks. The blocks could get cheaper (declining blocks-encourages use) or more expensive (inverted blocks-encourages conservation). This still is not the rate bob described.

The modern HUD rate is a version of the old hours-use rate developed by Arthur Wright of Brighton, England around 1896. The Wright rate but did not have a separate demand charge.

A few years before Wright, Dr. John Hopkinson devised a demand and energy rate (Hopkinson rate). Shortly thereafter, Henry Doherty proposed a rate which had a demand, energy, and customer charge.

The modern HUD rates may incorporate the customer and demand charges but the base rate energy is billed out in HUD blocks. Some things, like fuel cost adjustments and other riders, may not be billed in blocks.

These HUD blocks (or steps) are different from those in a step or block rate. The HUD rate is a load factor rate and is not as sensitive to the total kWh used, as is the case with step and block rates.
 
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