Why won't power utility company charge for kVA instead of kW

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  • #26
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Btw, if that was too much complexity you can assume your light bulb is the only thing on the line and calculate it that way. Then it is:
81.5 W if you include the line loss.
78W if you include the line loss and power factor's contribution to it.
OK, thanks, I see now where I was getting off in my thinking, and got similar numbers in a spreadsheet.

I'm correct that the PF causes some additional loss not captured in the residential $ savings label. So a CFL/LED with a PF 0.5 will cause the power plant to produce a few more watts than the same wattage CFL/LED with a PF of 1.0.

But due to the even higher IR grid losses with the 100 W filament bulb, the savings in fuel at the plant is even greater than the labeled watt delta would indicate. I didn't take my comparison far enough. And thinking in terms of 8% average grid loss threw me off, I needed to think in terms of each current's effect. There is some relatively fixed R in the lines, so less current means less % loss as well, the grid R is a smaller R relative to the CFL/LED.

I'll check out the other links that were provided along the way a bit later.
 
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  • #27
russ_watters
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Russ, that source you quoted confused power factor with harmonic distortion.
I know (sorry if I wasn't clear) - I purposely quoted a bad source as an example of the problem we've been discussing and brought up in post #14. Apparently the idea that reactive power has a significant impact on true CFL efficiency is a bit of a prominent anti-CFL myth. I didn't know it was so prominent until I googled for "cfl power factor" and that was a top hit. The article has multiple issues.
 
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  • #28
dlgoff
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Apparently the idea that reactive power has a significant impact on true CFL efficiency is a bit of a prominent anti-CFL myth.
Just had to reply;
[Off topic]
I looked for CFLs at a large grocery while food shopping yesterday. No CFLs or even a spot for them. Go figure.
[/End Off topic]
 
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  • #29
DrClaude
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Just had to reply;
[Off topic]
I looked for CFLs at a large grocery while food shopping yesterday. No CFLs or even a spot for them. Go figure.
[/End Off topic]
In my part of the world, CFLs have basically disappeared to the profit of LEDs. I don't think this is due to CFL myths, but rather to consumer economics.
 
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In my part of the world, CFLs have basically disappeared to the profit of LEDs. I don't think this is due to CFL myths, but rather to consumer economics.
Agreed. LEDs have a lot of advantages over CFLs, and now that the cost has come down on LEDs, the market is speaking.
 
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russ_watters
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In my part of the world, CFLs have basically disappeared to the profit of LEDs. I don't think this is due to CFL myths, but rather to consumer economics.
Agreed. My perception was the CFL myths (and a few legitimte concerns) slowed their replacement of Incs.
Agreed. LEDs have a lot of advantages over CFLs, and now that the cost has come down on LEDs, the market is speaking.
Er...could you tell me what they are, because they have been a problem for me. In particular, the economic benefit of CFLs over Incs was huge, but the economic benefit of LEDs over CFLs is essentially nonexistent.
 
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Er...could you tell me what they are, because they have been a problem for me. In particular, the economic benefit of CFLs over Incs was huge, but the economic benefit of LEDs over CFLs is essentially nonexistent.
Well, prices are all over the map for LEDs, I've got some on sale pretty cheap, no burn out yet, just a few bucks for dimmable, IIRC. I don't plan on buying another CFL in my lifetime, and I just bought some LED tubes to replace the flickering, buzzing tubes in my workshop. Probably no economic justification, the lights aren't on all that much, and the tubes are $17, but I get great light, and no buzz/flicker.

But I do feel LED often have advantages in quality of light, and no glass to break, no mercury fumes to worry about (and before anyone goes off on this, even though CFLs have small amounts of mercury, the form in CFLs, a kind of dust, is far more hazardous than liquid mercury), no start up issues. I like LED far more than CFL, and will pay a little extra for it. For most places where the light isn't on much, I stick with cheap filament bulbs if they provide the kind of light I need.
 
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  • #33
jim hardy
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For most places where the light isn't on much, I stick with cheap filament bulbs if they provide the kind of light I need.
I really dislike unnecessary complexity.
To replace simple filament lamp with one that requires
a pre-regulator for power factor correction and a switchmode power supply with active current regulation ,
both mounted in the base where they get heat-soaked in most ceiling fixtures so give a short service life
and exhibit aggravating time delay between getting switched on and illuminating the room
and catch fire if you use them with a dimmer
is irrational
especially in moderate climates where you need heat so much of the year.

I did find the dimmable warm white LED bulbs quite suitable for reading lamps . Whenever i find one in a thrift shop for less than a buck i buy it.

Can't beat my 200 watt Incandescent for the carport, though

old jim
 
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dlgoff
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In my part of the world, CFLs have basically disappeared to the profit of LEDs. I don't think this is due to CFL myths, but rather to consumer economics.
That's got to be right. All the "bulbs" that were available were the LED ones. I've yet to purchase one though. Guess I will now. :oldbiggrin:
 
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dlgoff
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To replace simple filament lamp with one that requires
a pre-regulator for power factor correction and a switchmode power supply with active current regulation ,
both mounted in the base where they get heat-soaked in most ceiling fixtures so give a short service life
and exhibit aggravating time delay between getting switched on and illuminating the room
and catch fire if you use them with a dimmer
is irrational
When the CFLs first came out, I wondered about all the rare earths that would be used. I just now did a Google search on "rare earths in cfl" and this consumer report was at the top of the list. Hell, I need to get out more. That report was from 2011. :redface:
 
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  • #36
jim hardy
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From Don's link:

We found that CFLs could pay for themselves in less than a year, saving you about $52 per 60-watt incandescent equivalent over the life of the bulb.
I like to check such claims.

$52 at 14 cents/kwh is 371.43 kwh which a 60 watt lamp will consume in about 6190.5 hours.
A CFL drawing 15 watts over that same 6190.5 hours will consume just 92.8 kwh, costing $13.00

So the saving in energy cost is about (52 -13 )$ / (6190.5) hours = 0.630 cents per hour (that's to three decimal places, $ 6.299976E-3)
that's a dollar every 1/0.00630 =158.8 hours = 6.62 days
To make $52 would be 52 X 6.62 = 344 days not quite a year.
So we might as well round off that energy saving number to a dollar a week if it's on continuously like my kitchen light .
Hmmm first time i've ever done this arithmetic.

They'll last a lot longer than a year if power isn't cycled often and the electronics in the base stays cool.
My kitchen light stays on continuously and the bulb mounts upright not base up like a ceiling fixture, so heat rises away from its base.. And since it's always on i don't suffer that aggravating initial dimness.
First CFL there lasted seven years so i made out like a bandit on it.
Second one lasted just a couple months
Third one i think three years, memory is growing dim
Fourth is in about year four now.

So even a curmudgeon like me has to admit
CFL's do have that one redeeming feature. I guess ....

old jim
 
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