December 02, 2009
Energy Efficient Light Bulb Manufacturing Energy Usage

German lighting company Osram finds that the energy used in making light bulbs is too little to affect total lifetime energy usage calculations. Compact fluorescents and LEDs really do save as much energy as their labeled wattages suggest.

The energy used during the manufacturing phase of all lamps is insignificant — less than 2 percent of the total. Given that both compact fluorescents and LEDs use about 20 percent of the electricity needed to create the same amount of light as a standard incandescent, both lighting technologies put incandescents to shame.

That's a great energy savings return on energy invested. Definitely low-lying fruit for anyone who wants to cut their energy bills who doesn't mind the light from CFLs or LEDs.

If you shop around on the internet you can find places that sell CFLs with different color distributions. Look for Kelvin numbers with lower numbers producing a yellower light and higher (4100K and up) producing a whiter light with more blue added. They also differ by Color Rendering Index. Perhaps a reader can describe better the differences to look for in CFLs?

Update: But a lot of CFLs do not perform as well as advertised.

Traditional incandescent bulbs, which are being phased out of British shops, lose just a fraction of their brightness by the time they stop working, but energy-saving ones lose 22 per cent of brightness.

The figures come from an in-depth report from E&T, the leading trade magazine published by the Institution of Engineering and Technology.

Buyer beware. Though I still expect CFLs to generate large net savings. Look for Energy Star rated bulbs as potentially higher quality.

Share |      Randall Parker, 2009 December 02 09:48 AM  Energy Lighting

random said at December 2, 2009 11:27 AM:

I bought some LED flashlights for camping this summer and the only comparison seems to be in lumens. The ones without a lumen rating on the package were so dim they were useless.

john personna said at December 2, 2009 12:25 PM:

To me it was always surprising that the MFG costs were assumed so high. An appeal to missing data perhaps, by lovers of the incandescent.

exception said at December 2, 2009 1:56 PM:

I use these people to get specs on bulbs:

I've never bought from them, but they explain color temps and CRIs. There's data to compare and contrast different types.

Reading the CRI specs on bulbs makes me hate my high pressure sodium street lights even more.

K said at December 2, 2009 2:35 PM:

The light from LEDs and CFLs doesn't bother me. I do find it harder to do detailed work such as threading a needle under LED light. But sensitivities vary, I easily ignore some noise in recorded music, etc. that bothers others.

But I hope they will improve the spectrum for commercially available LEDs quickly. The technology exists but is expensive. It would be so much better to skip past the intermediate step of using billions of CFLs around the world.

Exception: that is a good site for color temps, etc. Thanks.

Bruce said at December 2, 2009 3:31 PM:

"But a study carried out by a German consumer group found CFLs lose much of their brightness over their lifetime and can end up emitting just 60 per cent as much light as their nearest equivalent traditional bulb.
Researchers tested 18 CFLs over 10,000 hours and found an average reduction in brightness of 22 per cent. Three of the bulbs stopped working altogether.
Traditional bulbs lose no more than 7 per cent of their brightness by the time they stop working - which is around 2,000 hours after first being used.
Dickon Ross, editor of Engineering and Technology Magazine which published the research, said consumers were being misled."

Rob said at December 3, 2009 9:08 AM:

I think LEDs have a way to go, but that they will eventually win out. Since one "bulb" is made of several actual LEDs, then I expect commercial "bulbs" to eventually come in many different color mixes from blue to white to yellow. This ability to "tune" the light that is output will be nice. We may, eventually, see LED "bulbs" that can be dynamically tuned to suit the lighting needs of the moment - sort of like a three-way bulb, but including color. No doubt engineers somewhere are working like mad to increase the size of the radiating surface and drop the costs of each unit.

CFLs seem like a technology that will fade fairly quickly, unless real advances are made. Not only does their output decrease over time, but it takes up to 15 minutes to reach full brightness when you first turn them on. In addition, some of the ones I've bought have a really annoying lag between the time you throw the switch and the time the light starts to come out.

Wolf-Dog said at December 3, 2009 9:09 AM:

I have an LED-based desk lamp, and it is wonderful. I am sure that LEDs will improve a lot more in the future, so that all lamps at home will be this way.

Note that LEDs have very long life, and do not have mercury pollution danger like fluorescent lights. If the world switches to fluorescent lights, the danger of mercury poisoning will increase dramatically. Given the long life of LEDs, it might be better to focus on LEDs.

If we switch to LED lights at home, this might save significant power for electric cars!

Bob Badour said at December 3, 2009 1:33 PM:

The only LED lamp I have right now is in a 2" long flashlight I keep in my pocket. It's terrific. It's the handiest thing ever.

Nick G said at December 3, 2009 4:26 PM:

The very small incandescent bulbs in flashlights are very, very inefficient. That's a very good application for LEDs.

Similarly, incandescent bulbs achieve color with filters, which are very inefficent, so colored LEDs are a great application.

White light LED's? They don't really seem to be here yet in terms of cost or light quality.

morpheus said at December 3, 2009 5:31 PM:

since global warming was proved to be a hoax


who really cares about those fay leds?

Randall Parker said at December 4, 2009 5:21 AM:


Your stupid arguments are made worse by lack of punctuation and misspellings.

Rob said at December 4, 2009 12:27 PM:

See, that's the beauty of having a sane approach to energy use: YOU DON'T HAVE TO BELIEVE IN AGW TO BELIEVE WE SHOULD USE ENERGY EFFICIENTLY! I'm not a warmenist, but I still think using energy efficiently is a worthy goal. LED lights have the potential to not only use less energy (by a huge amount) than incandescent, but also to be better lights (cool to the touch, tunable in terms of color and very long lasting).

Same thing for cars. If hybrids or all-electrics are more efficient, then let's pursue them. Even if car exhaust doesn't cause global warming, it's still pollution and still bad to breathe, so let's get rid of it. If solar or wind power can be made cheaper than coal, then let's go for it. Dependency on foreign oil is bad, whether you believe in AGW or not.

AGW is mostly about political power. If it were really about the environment, we wouldn't see people from all over the world getting into private jets to fly to Copenhagen and Al Gore wouldn't live in a house the size of a state capitol. But you don't have to believe in AGW to want clean, efficient, politically sustainable power and transportation. Instead of being "green" you can just be smart.

Randall Parker said at December 4, 2009 12:40 PM:


I agree that the threat of global warming is not the only reason to switch to CFLs or LED lights. CFLs are cost effective. They save money. If you can find CFLs you like then why not save money?

I also think conventional pollutants don't get the attention they deserve. If we use less coal for electric power generation by cutting our electric power usage then we reduce conventional pollutants (e.g. particulates, oxides of sulfur, and other crap). If we use hybrid vehicles we reduce car pollution.

Plus, there's the cost of importing oil. If we use oil more efficiently or switch to substitutes we stop going deeper into debt to the world to buy the oil in the first place. We can't burn more and more oil because there's a limited supply and demand from developing Asia is rising.

I think the economic and conventional environmental benefits of more efficient use of energy are obvious and substantial. The heavy partisan debate about global warming obscures these benefits.

th said at December 4, 2009 3:11 PM:

"As the world prepares to converge on Copenhagen for the COP15 Climate Summit, Denmark’s Speaker of Parliament has expressed serious doubts as to the way in which the climate debate has developed.

“The problem is that lots of people go around saying that the climate change we see is a result of human activity. That is a very dangerous claim,” Parliamentary Speaker and former Finance Minister Thor Pedersen (Lib) tells DR."

Randall, the rats are jumping ship fast.

Since 1 degree F rise over 100 years is about to get wiped out resulting in zero warming where the models are at least 1 degree c rise at this point, whats the problem here? you, nickg, poet, got anything to help us out here?

Randall Parker said at December 4, 2009 3:43 PM:


How to think about global warming? Here's what I'm certain about:

1) Long term global climate models have large sources of error because:

- Some phenomena aren't modeled at all (e.g. nitrogen has only recently been added to a global climate model as I posted a few weeks back).
- Some phenomena (e.g. solar output, volcanic eruptions) can't be predicted.
- A lot of model pieces are rough approximations of processes not sufficiently well understood. Feedback loops therefore aren't as well modeled as we'd like.
- Computers aren't powerful enough. So level of granularity of the models leaves something to be desired.

2) The models aren't verifiable. We'd need parallel universes that run time at different speeds to verify them.

3) We can't do experiments on the climate to prove ideas about it. That's not allowed and we don't have multiple planets to experiment on to compare results.

4) Putting lots of CO2 into the atmosphere does really change heat loss by the atmosphere. So CO2 matters. But we can't figure out how much without knowing how the feedback loops play out.

Look back in history. The climate has gone thru big changes in just several years. It has gone thru big changes in just months after a big volcanic eruption such as in 1815. It could do this again.

In recent years the climate has stopped warming, at least according to some measures of global temperature. Skeptics point to it and say that the climate modelers didn't predict this. True enough. But that means that we do not know why the temperate stopped going up. Maybe more heat energy shifted into the oceans. Maybe feedback mechanisms we do not know about stopped the warming. Maybe the sun put out less energy. The sun's output could decline further or reverse. The climate could start going up again and even faster. It could cool. The climate is capable of major changes with our without our help. That's sobering and worrisome to me.

In the 20th century the human population exploded under fairly benign climate conditions. What happens if there's a major shift in climate in the 21st century? Starvation?

Bottom line: We can't know whether the climate is going to warm substantially in the 21st century. We can know we are injecting a lot of warming gases into the atmosphere.

View the climate with uncertainty and concern.

th said at December 4, 2009 6:29 PM:

Randall, is there an example in earth's history where CO2 is the definitive and undisputed single cause of anything?

Bob Badour said at December 4, 2009 6:47 PM:

While I am not Randall, I can answer that: CO2 triggers the involuntary breathing reflex. CO2 causes us to breathe.

Randall Parker said at December 4, 2009 7:16 PM:


This really is outside of a my areas of training or work expertise. I'm not an atmospheric physicist. I'm not a climate history scientist. You'd have to ask them. I know that people have used ice cores and other means to compare atmospheric CO2 and temperature in history. Some of those scientists have seen correlations. But I do not spend a lot of time reading about climate history.

Look, it is not easy to come to a well-informed opinion on climate research. I asked a brilliant Ph.D. physicist how hard it would be to know the research well enough to judge its quality and the likelihood of human-caused global warming. He thought he'd have to spend a year studying the research to come to a well-informed opinion and he has the technical chops to do so. He said he can at least tell when total deniers haven't done their homework and most of them haven't.

I also talked with a planetary scientist (he studies other planets) and he said the climate models have big sources of error in them and aren't predictive.

The vast bulk of the people who feel certain about this subject are deluded. There might well be people who feel certain who have enough knowledge to know. I'm not sure.

Brett Bellmore said at December 4, 2009 8:50 PM:

"2) The models aren't verifiable. We'd need parallel universes that run time at different speeds to verify them."

On the contrary, we need only wait. Admittedly it's not a fast way to verify them, but it is a means of doing so. And while we were waiting for the data to roll in, all the technology we'd need to respond to what it told us would improve.

I might buy retrodiction, 'predicting' events in the past, for a model that was purely driven by physics. For models with this many free parameters, only PREdiction cuts it, anything else is just curve fitting with excess degrees of freedom.

Randall Parker said at December 5, 2009 7:22 AM:


Our single universe is not enough to verify even a single model. A model might match the real world events by luck. There are enough models run with enough variations of constants that one might come out looking good in 2100. Does that make it correct? I do not think so.

Our problem is that the system under study is so incredibly complex that we can't create correct models. We can make better models and then even better models still. They'll keep getting better. But we can't make policy decisions today based on certainty about what'll happen without policy changes or with policy changes.

Suppose CO2 really is going to heat up the climate so much it'll melt the glaciers in Greenland and, among other things, put much of our coastal areas under water. Waiting to do something about it until the technologies are cheaper might not be a good idea. The CO2 will already be in the atmosphere. Do you expect it'll be cheaper to remove the CO2 from the atmosphere in 2040 than it is to prevent its emission in 2010, 2020, and 2030?

I look at coal versus nuclear and see that nuclear isn't enormously more expensive. It isn't like solar PV which is multiples more expensive. I think it seems a prudent fairly low cost thing to switch from building new coal electric plants to building nuclear electric plants. One or two cents per kwh more isn't a big burden. The CO2 emissions problem might be real. So why not switch away from coal as old coal plants get retired and it is time to build new generating capacity?

th said at December 5, 2009 4:48 PM:

Randall, The lack of evidence supporting any of this is the bigger story, not that the models failed. The whole idea was pushed hard lacking anything substantial, a theory that fails every test is still a failure. You have to do better than pleading. We've been blowing this stuff out for over 200 years, the entire warming may very well have been just sampling points in parking lots. A slight cooling trend over the last 5 or 6 years is wiping out that 1 pitiful degree. Anecdotal evidence is really all this fraud has thrived on, another computer game isn't the answer.

Engineer-Poet said at December 5, 2009 5:41 PM:

Just keep telling yourself that, th.  Warm winters and the consequent pine-bark beetle infestations are killing forests well up into Canada.  The northern sea route around Canada was ice-free.  A guy went swimming at 90°N in 2007.

When this little local shift in the USA shifts back, people like you are going to be VERY unpopular.

Brett Bellmore said at December 6, 2009 7:51 AM:

"Do you expect it'll be cheaper to remove the CO2 from the atmosphere in 2040 than it is to prevent its emission in 2010, 2020, and 2030?"

Quite possibly, especially if we can get some kind of self-reproducing nanotech working by then. Perhaps more to the point, by 2040 we'll actually have some confidence as to whether or not this is a real problem, deserving of doing something massively expensive to fix. If it's an emergency meriting massive expenditures, they ought to go first into understanding the nature of the emergency, so our subsequent response is correctly applied. Wouldn't it be a real bummer to turn down the thermostat at just the moment our climate decided to rebound into an ice age? Who knows, maybe ice ages DO begin with a temperature rise, followed by a plunge.

The recent revelations haven't proven global warming a hoax, but they've established pretty clearly that the whole field is going to have to go through a period of enhanced transparency, and OPEN data collection, before anybody should have confidence in it's conclusions.

In the meanwhile, I'm quite convinced that we should be going heavily into nuclear power. We could achieve energy independence through nuclear power a hell of a lot more cheaply than our current expenses trying to keep the middle east from catching fire. And I do kind of like coral.

Nick G said at December 6, 2009 12:10 PM:


Brett has an awfully good point with "I do kind of like coral."

That's a point you need to add to your summary: CO2 emissions have effects beyond the atmosphere, and the big one that I know of is ocean acidification. I haven't seen any counter-evidence (or even counter arguments) to the notion that rising atmospheric CO2 levels are acidifying the oceans, and that this will be catastrophic for ocean life (especially things like coral and various forms of shellfish).

th said at December 6, 2009 3:31 PM:

poet, the northwest passage was open in the early 1900's and in the forties, something east anglia found particularly annoying.

...from Global Warming Science Fiction's Tim Wrigly at NCAR to Phil Jones on how to use the Mike Mann data trick.

"Here are some speculations on correcting SSTs to partly explain the 1940s warming blip.I believe if you look at the attached plot you will see that the land also shows the 1940s blip (as I'm sure you know).

So, if we could reduce the ocean blip by, say, 0.15 degC, then this would be significant for the global mean — but
we'd still have to explain the land blip.?"

This is apparently after reading Harry Potter, the cloaking device used by all then is being replaced by a bucket of whitewash from Lowe's.

peter dublin said at December 7, 2009 3:57 PM:

I agree that all lights have their uses
but that doesn't justify banning any one type

CFLs don't save as much energy as thought...

RE energy used in Osram manufacturing
There's a lot more to it than that

1. That's the Osram assembly of already complex parts -
there's the manufacture of all the parts to take into account too

2. Transport (from China!), transport to recycling, recycling process, transport of mercury (etc) back to China, as under negotiation,
for reuse in new CFLs

3. CFL power factor, halving supposed energy savings in terms of energy needed at the power plant

4. Lifespan issues
CFLs lab tested in 3 hour cycles, not corresponding to real life use, on-off switching substantially cutting life

Also brightness testing not equivalent to practical use,
heat factor of ordinary bulbs in temperate climates,
and a lot more from onwards

peter dublin said at December 7, 2009 4:08 PM:

On a broader point Re Copenhagen, as in the comments

Whatever about the climate science,
there is actually no need to justify CO2 reduction as such.

Changes in electricity and transport (80% of CO2 emissions) should be
done anyway for very different advantages,
including electricity bills that are lowered from opening up
electricity grids to competition,
that can also have smart meters set to automatically give the cheapest (and/or
greenest) electricity at any time,
which might also be powering some cars

The simple focus on the largely local electricity and transport sectors,
avoids expensive meaningless emission trading (cap and trade) with its
avoids international tension arising out of trade with less regulated countries,
avoids alienating people by telling them what Light Bulbs or TV sets
they can or cannot use,
and easily meets 2020/2030 emission targets.

In 2020/2030 - if CO2 reduction is still seen as warranted - other
industries can be involved.

Otherwise, nothing has been lost.

Re Copenhagen and politicians saying
"We must all cut down to save the planet"

There is no energy shortage
(given renewable/nuclear development possibilities, with CO2 emission
limits set as deemed necessary)
and consumers – not politicians – PAY for energy and how they wish to use it.
Notice: If there WAS an energy shortage, its price rise would
– limit people using it anyway, and make renewable energy more attractive
– make energy efficient products more attractive to buy.
No need to legislate for it.

And since when do light bulbs, TV sets etc give out any CO2 gas?
Not like cars.
And cars are taxed.
They could of course tax the bulbs etc, and lower the tax on energy
efficient alternatives.
Governments make money on the reduced sales, they can pay for CO2
emission processing and renewable energy, and consumers keep choice.
Taxes are unjustified, but better for all than bans.

Few seem to know about the industrial politics behind the supposedly
environmentally justified bans

Randall Parker said at December 8, 2009 5:25 PM:


We know there are lots of natural climate feedback loops and sources of varying input (sun, volcanoes, etc). We expect the climate to vary quite a bit naturally. Therefore we should not expect a constant slow change in one direction. Even if humans are influencing the climate in one direction we shouldn't expect to get there in a straight line.

As I keep trying to say, we can't prove our influence. But we can't also prove the converse either. We can't prove the lack of our influence. Why? The climate is too complex to model and we can't compare parallel Earths in parallel universes.

Randall Parker said at December 8, 2009 5:38 PM:


Yes, we have other reasons to use non-fossil energy sources. The debate over global warming obscures the advantages of ending our dependence on expensive oil imports and the advantages of energy sources that do not spew conventional pollutants.

Carthago Delenda said at December 9, 2009 12:15 AM:

My two cents:

have no serious proof about it, and even though it reasonable to estimate that anthropogenic things have some sort of effect
on other things, there is probably no real means to measure the size of that effect, until it's too late.
Just like the existence of God, may add somebody.

don't know jack what are they talking about, and are unable to understand what their grant-depending advisers say,
but know very well that "EEEEEK we all are gonna die! But I can save you" is a great slogan.

As a consequence we have anti AGW regulations that have nothing to do about the alleged AGW at all, like that "crap and trade" thing.
In short the AGW religion is the best and most effective excuse for the people that really pollute around.

On the other hand, energy efficiency necessarily has an effect on pollution, wallets, and AGW related emissions
cause we burn less stuff to feed the engines
and therefore should be pursued.

(I hope it's properly written... sorry for my bad English,
I am just a barely serious person coming from a small island about 120 mi from Africa...
so don't go all racist on me, please. ;-))


Nick G said at December 10, 2009 10:34 AM:


Your source for energy consumption in CFL manufacturing is about 20 years old - that's too old.

Also, a 50% power factor doesn't double power consumption - just amperage. That increases line losses, and has some other costs, but nothing close to a factor of two.

peter dublin said at December 10, 2009 11:47 AM:

Nick G,

RE CFL manufacturing
There are other sources too on my website onwards
and thought they also deal with other lack of savings from overall CFL lifecycle

Besides: The underlying facts haven't changed
Osram CFL manfacturing study is about the ASSEMBLY of many already manufactured parts.
The energy of the manufacture of the PARTS has to be taken into account.
Ordinary light bulbs have very few parts.

RE CFL power factor
CFL power factor is typically 0.5 - 0.6 and NOT ONLY involves
around twice the energy delivery from the power station to deliver the same watts at your home,
but also more costs for the harmomic distortion etc problems set up in domestic distribution grids
typically not set up to handle them.

See the specifically described example here:

For the 60 watt incandescent lamps:
· Customer pays for 60 watts of power
· Utility generates 60 watts ÷ 1.0 PF = 60 VA

For the 15 watt medium-based compact fluorescent lamp, electronic ballast,
· Customer pays for 15 watts of power.
· Utility generates 15 watts ÷ 0.6 PF = 25 VA

(around a half of what power station needs to deliver regarding the incandescent lamp
= NOT 1/4 as typically calculated as energy savings, then based on 15 watts x 4 =60 watts )

Of course the consumer ends up having to pay for that too,
though it doesn't show on the meter (as industrial customers have to do today)

There are as said in previous comment plenty of other reasons the supposed savings aren't there.

peter dublin said at December 10, 2009 3:18 PM:

Nick G
I have answered your last objections, but it hasn't appeared on the website
Maybe too long / reference links used
Will see if this appears...

peter dublin said at December 10, 2009 3:48 PM:

Perhaps comment appears some time.

Otherwise, briefly (and cutting off link URLS):
1. RE manufacturing energy used
There are plenty of other references on the site eg and that also take it up,
with other reasons CFLs don't save
as much as supposed.
Besides: Osram data is just for ASSEMBLY anyway - not include manufacture of the PARTS
That has nothing to do with age of research.
Open your CFL bulb and compare that with an ordinary light bulb!

Power factor, no indeed, - power station has to do around twice the energy output
to deliver the same wattage
(CUT url these add h t t p : / / =)
general explanation
If you want to see comparative light bulb stats see

They compare a 15 W cfl and 60 w ordinary bulb
energy used to power 15 w bulb = around half of 60w = not 1/4!
And that is using 0.6 power factor (it is often .5-.55)
They say -qute rightly - it doesnt show on your meter but you end up having to pay for it of course.
Also, that is not including the extra cost of doing up the typically untreated domestic grids to deal with the harmonic distortion etc also set up by CFLs

In fact that is why industry is penalized if they don't balance the load they present.

All that said,
I don't like supporting ordinary light bulbs just by criticizing CFL savings
It's too easy just to start talking about Halogens or LEDs or whatever.

Really all lights have advantages- just buy what you want to use.
Sure - there might be a little savings here or there.
But that is only ONE reason to choose a light,
given light quality, appearance, construction, response etc differences between different lights.

As for bans,
Any energy /emission problems can and should be dealt with directly,
leaving consumers alone:
If that's not judged enough, light bulb taxation is better than bans, as said in a previous comment, giving government income on reduced sales yet keeping choice.

Nick G said at December 11, 2009 10:21 AM:


Keep in mind that the energy used in manufacturing is small enough that it's not really important, even if it does increase. A 25W CFL will save at least 25W - if it only lasts 2,000 hours it will save 50 KWHs. A CFL can't possible need 50KWH to make.

Regarding power factor: VA doesn't equal watts. A high power factor raises amps, not watts, so it doesn't increase power consumption.

peter dublin said at December 11, 2009 12:43 PM:

Nick G

RE manufacture:
You seem to agree that it's not taking into account of all factors.

Ofcourse it alone might not wipe out all the savings, even with shorter lifespan,
but then there are other factors - as said:
For example,
The brightness is measured in ways that do not conform to practical use and is less than stated anyway
Heat factor similarly esp in temperate countries
-- etc with al other factors as mentioned on
You might check on that too - as said...

Sure there might be some small saving at the end -
but why the incessant push to get people to use something to save energy,
rather than what they actually might want to use - and pay for.

Power factor
You started off by saying "it's just current" (amps) so that's an improvement.

Actually VA, Volts Amps, does equal watts, in the sense watts = volts x amps
It's just called 'VA' because the phase difference in the voltage and current cycles in production.

Just google 'VA' 'watts' and 'difference' and find out
(obviously from several/reputable sources if you want to be sure).

Power companies generate power in VA.
You only pay for Watts used, so there's a lot of power lost in the lines and transformers in trying to overcome a poor 'power-factor'.
If what you said was true, industry would not be penalized for even small drops in power factor presented as a load to the power company.
Typical cheap CFLs have around half the PF of ordinary bulbs (balanced CFLs are rarer and cost considerably more).

peter dublin said at December 11, 2009 12:46 PM:

Re power factor,
VA aka 'Volt-Amperes' if you want to look it up.

Nick G said at December 11, 2009 4:04 PM:


Actually VA, Volts Amps, does equal watts, in the sense watts = volts x amps
It's just called 'VA' because the phase difference in the voltage and current cycles in production.

Ah, but the phase difference is crucial. If at a point of time the voltage is high, but the amperage is low (i.e., they're out of phase) then the watts (power) are lower than a simple VA multiplication.

Now, as I said above, a low power factor increases amps, and that increases line losses, and has some other capital related costs, but nothing anywhere close to the ratio of VA to W.

peter dublin said at December 12, 2009 4:54 AM:

Nick G
re "nothing anywhere close to the ratio of VA to W"

Any outsider reading this can look it up for themselves.
Power factor loss IS the difference between VA (power generated) and watts (power as registered on consumer meters)!
Consumers of course end up having to pay for ALL the power generated at the power station.

In fact, if you bother to read the links I keep giving,
The USA Dept of Energy illustrates the concept very well with a horse pulling a load,
and Sylvania uses a glass of beer analogy.

There are many other points that mean CFL use does not give supposed savings,
as said above with more listed from onwards.

Whatever (marginal!) savings there are at the end of the day,
people can compare with other advantages that different lights have for them.
If Nick or anyone else feels CFL use is great - why not!
Everyone should be allowed to use what they want and energy/emission issues dealt with directly, as explained.

Engineer-Poet said at December 12, 2009 2:08 PM:

I don't have to look it up, Peter.  VA is used to size transformers and lines, but turbine output is rated in watts.  Lagging current at the fundamental can be offset with capacitors, and don't even try to tell us that capacitor banks dissipate 1 W per VA generated.  We will laugh you off the site.

Harmonic content is an issue but it can be worked around.  Harmonics can be filtered and bypassed as required, and also compensated in the devices themselves (the same electronic techniques which control DC current in the fluorescent tube can be used to shape the bulk of the input waveform).  Third harmonics are generated in transformers and are bypassed using delta windings (even in wye-wye transformers there will usually be delta windings to handle the third harmonic).  These things go back as far as the first three-phase section of the line and don't get any further.  Higher harmonics tend to be consumed as eddy currents in transformer iron, isolated by line reactance and shunted to ground by PF correction capacitors.

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