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CFLs Causing Utility Woes
Posted by
timothy
on Wed Apr 08, 2009 04:50 PM
from the so-very-simple-that-only-a-child-can-do-it dept.
from the so-very-simple-that-only-a-child-can-do-it dept.
dacut writes "We've seen compact fluorescent lamps start to take over shelf space at the local hardware store. Replacing a 60 watt incandescent with a 13 watt CFL seems like a great savings, though many consumers are disappointed with the slow warm-up times, lower-than-advertised lifetimes, and hassles of disposing the mercury-containing bulbs. Now EDN reports they may use more energy than claimed due to their poor power factor. Mike Grather, of Lumenaire Testing Laboratory, 'checked the power factor for the CFLs and found they ranged from .45 to .50. Their "real" load was about twice that implied by their wattage.' The good news: you're only billed for the 13 watts of real power used. The bad news: the utilities have to generate the equivalent of 28 watts (that is, 28 VA of apparent power for you EEs out there) to light that bulb. Until they fix these issues, I'll hold on to my incandescents and carbon arc lamps, thanks."
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[+]
Incandescent Bulbs Return To the Cutting Edge 569 comments
lee1 writes "A law in the US that is due to take effect in 2012 mandates such tough efficiency
standards for lightbulbs that it has been assumed, until recently, that
it would kill off the incandescent bulb. Instead, the law has become a
case study of the way government regulation can inspire technical
innovation. For example, new incandescent technology from Philips that
seals the traditional filament inside a small capsule (which itself is
contained within the familiar bulb). The capsule has a coating that
reflects heat back to the filament, where it is partially converted to
light. The sophisticated ($5.00) bulbs are about 30% more efficient than the
old-fashioned ($0.25) kind, and should last about three times as long.
So they are less economical than compact fluorescents, but should emit a
more pleasing spectrum, not contain mercury, and, one supposes, present
the utility company with a more desirable power factor."
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Still... (Score:5, Interesting)
Re:Still... (Score:5, Informative)
I agree, and even if the article is 100% accurate, you are still saving more than 50%.
About 3 months ago I decided to switch over, and since then I've been slowly replacing all my incandescents with CFLs as they burn out. I was initially afraid of the flicker factor, since the flourescent tubes in my laundry room flicker like crazy and give me headaches when they are first turned on, especially when it's cold. However, I haven't really noticed any flicker with the CFLs so far.
As for the lifespan, it is kind of silly how they report it (9 years, but only if you use each bulb less than 3 hours a day), but it's still longer than an incandescent.
So basically yah, CFLs aren't the best we can do, but they're the best affordable replacement for incandescents we have so far.
Parent
LED is a viable option in 40 Watt replacement (Score:5, Interesting)
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Re:LED is a viable option in 40 Watt replacement (Score:5, Interesting)
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Re:LED is a viable option in 40 Watt replacement (Score:5, Informative)
Here's the problem with LEDs. Yes, LEDs have extremely high quantum efficiencies.... in the *red and blue spectrum*. There are no efficient yellow and green LEDs; it's called the "green gap". But it just so happens that's where our eyes are the most sensitive; we're insensitive to red and blue, but sensitive to yellow and green. So-called "white" LEDs are usually just blue LEDs with a phosphor coating that wastes some energy to create a lower frequency spike, enough to make it look roughly "white" (but in general they're often still blue dominated, making it somewhat of an irritating color). There are "warm" LED bulbs that make a stronger low-frequency signal with phosphors, but that wastes even more energy.
The other main complaint about LEDs is flickering, but that's trivially remedied; good bulbs are full-wave rectified, unlike the cheapo ones that are half-wave rectified and flicker.
The net result, however, is that LED bulbs for lighting tend to be only marginally more efficient than CFLs in terms of lumens, if that, and tend to have more irritating colors. We need to close the green gap.
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Re:LED is a viable option in 40 Watt replacement (Score:5, Informative)
Still, as demonstrated on the Myth Busters a while back, LED bulbs can be turned on and off many more times than other kind of bulb. This can make them last substantially longer than anything else and should be factored when considering their efficiency and cost I believe.
It looks like there's a few ways of creating white LEDs, including using separate red, green and blue LEDs (although this is rarely mass produced) and using near UV emitting LEDs in a similar fashion that you described, which results in a better color spectrum but with the risk of emitting UV light if there's a manufacturing flaw.
I learned this from http://en.wikipedia.org/wiki/Light-emitting_diode#White_light [wikipedia.org]
In addition, I learned why white LEDs get so hot--it's due to the Stokes shift which happens when the blue LED light is shifted to white via the phosphor coating.
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Re:LED is a viable option in 40 Watt replacement (Score:5, Insightful)
I think your information is basically wrong. Perhaps you've been buying the wrong lights. The lumen ratings for bulbs take the human visual color response into account, so a "white" LED of 100 lumens is dumping a pretty good load of light into the green range. The color temperature on the most efficient LEDs is a hair off (looks like a welder's torch to me), but their light is as good as what you get from similarly efficient fluorescent bulbs. The LEDs I have in mind are the relatively recent CREE XRE power LEDs, that run at between 350 and 1000 mA.
If you are willing to take a minor efficiency hit, go for a quality "neutral white" LED, and you get pretty good light. I did this for the lights under our kitchen cabinets [wordpress.com], and it is great.
You are correct that there are no efficient "direct" green LEDs, but the phosphor downconversion is no different from how it is done in fluorescent lights, and because the initial light is not confined to a small number of wavelengths, the resulting light is better looking. I initially got this information from a physicist (we were taking our kids on the same ski trip) and I later confirmed it for my own self with a diffraction grating [wordpress.com]. By-the-way, if you look at those diffraction-grating pictures, you will see that the white LEDs do indeed emit a good amount of yellow and green.
If you see flickering in your LEDs, you are using a truly cheap regulator. All the ones that I use are built around switching power supplies for efficiency, and their "flicker" is in the 10-100 kilohertz range. As far as durability goes, I have generator-driven current regulated LEDs on two of my kids' bikes and two of my bikes, and they ALL live outdoors, one not under any cover, in Massachusetts, year round. The kitchen lights are on almost continuously, since they are the most efficient lights in the house by far. Most important to long lifetime, is adequate heat sinking, and/or not over-driving the lights (they're also more efficient at lower power, even holding the temperature constant, and they're more efficient at lower temperature, which is a side-effect of lower power when you don't hold the temperature constant).
Where the heck did you get your information? If this is from lights that you've bought/used, I'd love to know which ones, so that I will never buy them by accident.
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Re:LED is a viable option in 40 Watt replacement (Score:5, Interesting)
I've purchased LED lights for my house and was extremely disappointed with their performance and efficiency. However, as you said, the Cree XRE and other recent high power LEDs can be made into very efficient and nice looking lights. Problem is, they haven't yet - at least not that I have been able to find. As far as I have found so far, the LED manufacturers have the goods, but the light "bulb" manufacturers have not yet taken advantage of all the latest LED tech.
There's also the typical BS found in many new industries where cheapo manufacturers take advantage of the hype and produce sub-par products at very low prices. It's an easy one in this case because one of the major points is cost. This should shake out eventually and we'll see better quality products hit the market. I just want it to hurry up.
I hate CFLs because the ONLY good thing about them is their lower power consumption. But to manufacture them is very dirty and they have mercury in them, so they can't be disposed of cleanly either. I don't like the slow start up speed or the color temperature. I bought a few packs of CFLs before finding all this out so I'm still using them. But I will not buy any more. I'm dying for LEDs to come to the main stream.
It's not a surprise to find that the power factor of CFLs sucks too. Again, cheapo manufacturers trying to cash in on a trend. Quality manufacturers know how to handle power factor problems.
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Re:LED is a viable option in 40 Watt replacement (Score:5, Funny)
Making it lit with light of a different tonnality just stresses you.
Right. The flipside of that is a fire. Whenever I go to a bonfire, I'm astounded at how everyone is instantly hypnotized by the dancing flames.
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Re:LED is a viable option in 40 Watt replacement (Score:5, Insightful)
http://www.energystar.gov/ia/partners/promotions/change_light/downloads/Fact_Sheet_Mercury.pdf [energystar.gov]
The above link explains lots of misconceptions about CFLs like discussed earlier here. ...
Excerpt below:
What are mercury emissions caused by humans?
EPA estimates the U.S. is responsible for the release of 104 metric tons of mercury emissions each year. Most of these emissions come from coal-fired electrical power. Mercury released into the air is the main way that mercury gets into water and bio-accumulates in fish. (Eating fish contaminated with mercury is the main way for humans to be exposed.)
Most mercury vapor inside fluorescent light bulbs becomes bound to the inside of the light bulb as it is used. EPA estimates that the rest of the mercury within a CFL â" about 14 percent â" is released into air or water when it is sent to a landfill, assuming the light bulb is broken. Therefore, if all 290 million CFLs sold in 2007 were sent to a landfill (versus recycled, as a worst case) â" they would add 0.16 metric tons, or 0.16 percent, to U.S. mercury emissions caused by humans.
How do CFLs result in less mercury in the environment compared to traditional light bulbs?
Electricity use is the main source of mercury emissions in the U.S. CFLs use less electricity than incandescent lights, meaning CFLs reduce the amount of mercury into the environment. As shown in the table below, a 13-watt, 8,000-rated-hour-life CFL (60-watt equivalent; a common light bulb type) will save 376 kWh over its lifetime, thus avoiding 4.5 mg of mercury. If the bulb goes to a landfill, overall emissions savings would drop a little, to 4.0 mg.
EPA recommends that CFLs are recycled where possible, to maximize mercury savings.
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You can fix your laundry room bulbs (Score:5, Informative)
It is possible the bulbs are just old/damaged and new bulbs would do better but most likley it is the ballast. Old ballasts were mechanical and operated at line frequency. This means that you are going to get flicker at 120Hz since it crosses the null 120 times per second. That is noticeable to some people.
New ballasts, including those in CFLs, are electronic. They cycle at a much higher rate, generally in the realm of 30kHz, because that's more efficient. That also gets rid of visible flicker, of course.
So what you need to do is replace the ballasts. You can get new ones at any home supply store. Alternatively you can just replace the whole fixture, new ones will come with ballasts. Should stop your flicker, reduce your power draw, and last longer to boot.
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Re:Still... (Score:5, Insightful)
CFLs are currently where LCD monitors were 10 years ago: the advantages are intriguing, but the quality of the current product lines is scattershot, there are some significant engineering and manufacturing hurdles left to deal with, and there are a lot of people denouncing the new technology mostly because they're afraid of change. All of which will be overcome in the next few years.
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Re:Still... (Score:5, Interesting)
Looking a bit further ahead, another company called Vu1 has a novel idea for a light which uses electron stimulation against phosphor to produce light (sorta like a crt). It has no mercury and is also dimmable. It's also shaped like a regular incandescent so lamp shades will fit on it. They will be less expensive than LEDs and produce much better color rendering, but they will likely cost more than CFLs.
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Harshness is all about color temperature (Score:5, Informative)
Most people are used to "soft" or "warm" light from incandescents -- low color temperature. Most early CFLs were "cool" or "daylight" -- high kelvin temperature. Now you can get both, but "warm" (low color temperature). are more common because that's what most people prefer. Check the color temperature on the box before you buy!
Also, if you have flicker or a buzz, or a slow startup, you got a low quality bulb. Return it and get a different brand. Or buy several and see which ones you like the best. Good CFLs don't flicker or buzz, and they start up essentially instantly. There is a lot of variety between brands and models. And quality averages way better than it used to, although there still are some bad apples out there.
And I haven't seen any reasonably priced dimmable CFLs to test out (do you need a special dimmer?)
I got several cases of dimmables on Ebay a couple years ago, and they work just great, on my normal dimmers. Don't remember the brand, but I could get it for you at home if you need it.
By the way -- how many Slashdot articles (like this one) are we going to have full of people trying desperately to come up with a way to justify their decision to spend *way* more money in electricity and increase emissions because they're too lazy or stuck in their ways to merely change their lightbulbs? I mean, come on... is power factor really the best they can come up with? Really, if that's your excuse, just buy a freaking high power factor bulb. Yes, they exist, and have power factors in the 0.9 to 0.95 range. But even with low power factor bulbs -- since when is 1/4 (CFL apparent power consumption relative to incandescent) * 2 (power factor=0.5 CFL) greater than 1.0 (incandescent)?
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Re:Harshness is all about color temperature (Score:5, Interesting)
Fluorescent bulbs don't have color temperatures defined.
Yes, they do. Look at the box.
Fluorescent bulbs are very much band-limited, unlike broad band black body radiators.
And the color temperature rating for fluorescents is based on the weighted average of where its power output lies.
Heck, they do an okay job of offsetting your heating bill, in the winter.
Electric heat is inefficient. And electric heat in the summer means more AC. Adding extra heat to your house is overall definitely not a good thing.
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Re:Harshness is all about color temperature (Score:5, Informative)
I was on the board of our rather large condo complex and wanted to replace the 100 or so incandescent bulbs outside with CFLs but was afraid of the cold factor (it gets to -40 sometimes where I live). So, I took four brands of CFLs and did a controlled experiment: stick two of each brand in the deep freeze overnight, then quickly screw them into sockets to how well they light up. GE and Sylvania 's ballasts punked out, even after warming up. The only brand that worked completely was Globe, the cheapest of the bunch, so don't always go by price. We switched the bulbs in 2005, and haven't replaced a single one yet. They are controlled by photo sensors, so on and off once a day, with no hiccups even in the cold...
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Re:Still... (Score:5, Interesting)
You say "run of the mill", but IIRC the only brand that hasn't died at all yet in the Consumer Reports lifetime test is GE.
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Power factor compensators (Score:5, Informative)
Since a CFL consumes a exactly constant amount of power it shoul dbe trivial to put in an inductor and capacitor in the package to exactly compensate for it.
Moreover if the power factor is really 0.5 then it seems like just having two of these running in quadrature ought to null the power factor back to 1.
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Re:Power factor compensators (Score:5, Funny)
This is /.!
No thinking!
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Re:Power factor compensators (Score:5, Informative)
It is in fact, you can make a fluro light appear to your meter to use zero power (with the right inductor/cap combo).
Its illegal afaik in most countries though.
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Re:Still... (Score:5, Informative)
Some day there will be a report of all the damage to the environment being caused by discarded CFLs and people will wonder what the hell we in this century were thinking, replacing low-pollution cheap lights with mercury-containing costly electronics gizmos
How many times does this myth have to be knocked down? It's like fighting a zombie.
1) Coal power plants, which make up half of our electricity production, are the prime emitters of mercury in the world, and emit more, straight into the air, powering an incandescent bulb than a modern CFL would emit if you took all of its contents and vaporized them straight into the jet stream.
2) Where were you complaining about mercury when fluorescent tubes became the standard for offices nationwide many decades ago? These use over an order of magnitude more mercury.
3) Mercury in fluorescents is so-called "inorganic" (elemental) mercury. Most mercury emitted by power plants is "organic" mercury (mainly methylmercury, but also some dimethylmercury). Organic mercury is far more toxic.
4) Even just throwing a CFL in the trash doesn't mean all that mercury is emitted to the environment. I could dig up the link *yet again* if I have to, but the amount of mercury released from CFL disposal is roughly along the lines of: 20% if your trash is incinerated, 3% if it's landfilled, 3% if you throw the bulb into normal glass recycling, and a small fraction of a percent if it's treated as hazardous waste.
Modern CFLs use a really, really tiny amount of elemental mercury -- about the mass of ten grains of salt. What's going to be the next scare over -- the radioactive americium in smoke detectors?
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Re:Still... (Score:5, Funny)
"What's going to be the next scare over -- the radioactive americium in smoke detectors?"
Now I need a lead foil hat...
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Re:Still... (Score:5, Funny)
Just move to Canada. Our smoke detectors use radioactive canadicium instead.
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Re:Still... (Score:5, Funny)
Chemical symbol: Eh
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Re:Still... (Score:5, Informative)
A modern CFL, the low-mercury kind that's starting to dominate, has only about 3mg of mercury in it. That's about the mass of ten grains of salt. Compare that to how kids used to play with whole balls of the stuff from thermometers -- and you're worried about ten grains of salt worth, a fraction of which might have left the bulb? On top of that, it's elemental mercury, which is far less toxic than mercury bound up in organic compounds (like you find in food, or power plant emissions). And it's not a dust.
Every so often you'll get some scare story about how somebody broke a bulb, and they had their mercury levels in the room checked and it was X times over the OSHA standards. But those standards are for chronic exposure, and we're talking about levels that fall off exponentially over time. For crying out loud, if you're concerned about tiny amounts of mercury in your body, there are a lot better ways to prevent it than worrying about CFLs. Like cutting down on seafood, or having any amalgam fillings removed from your teeth. And if you care about mercury in the environment, you should absolutely *not* be using incandescents, as coal power plants are our primary mercury emitters.
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Re:Still... (Score:5, Informative)
The vast majority of my electricity usage is not from light bulbs, despite what most pro-CFL people would have you believe.
What an amazing discovery! So, you're telling me that I can change how much money my lightbulbs are costing me to run simply by wasting power or not wasting power elsewhere?
(Translation: Please, be serious here; the cost to run your bulbs is independent of where you waste power elsewhere.)
Let's say I save $4/month after I spend $40 on the bulbs.
Let's say I live 100 years by eating more sunflower seeds. Now let's decide what to do with those 100 years.
(Translation: No, pulling numbers of a hat doesn't count as doing the math).
You're really going to make me do this again, aren't you?
75W bulb -> 19W CFL = 56W difference
56W * 3h/day * 0.001kWh/Wh * 365.24 days/year * 0.11 dollars/kWh = $6.75/year
Multiply by however many bulbs you'd like. Note that we're not counting the contribution to AC/heating (which nets notably worse for incandescents).
Oh, and if your answer is, "Well, perhaps that'd justify my living room, but not Room X, because I don't use the lights in there that often" -- well, then they won't burn out that often either, now will they?
Parent
Re:Still... (Score:5, Informative)
Most of the bulbs in my house are 60W, not 75W, and I'm paying $0.09/kWh, which puts it at $4.04/year
Assuming you use them only for a mere three hours a day and don't count the dollar-or-two-per-incandescent-bulb contribution to your AC costs.
each bulb costs $2.50, remember
And incandescents are free?
Let me say that again: a single CFL burn-out changes my total yearly savings from $1.54 ($4.04 - $2.50) to -$0.96!
So, you live in a world where incandescents are free and you only use your bulbs for an average of a mere three hours a day, and incandescents don't increase your cooling costs, and despite only three hours of use per day, your bulbs burn out in six months. Right.
I live in the real world, which is a very different place. I've used CFLs for about three years now. The whole house has been on CFLs for at least two years. I've taken burned-out bulbs to the dump once before -- six or so of them, tacked on to another dump trip. I just checked my bag of bulbs that have accumulated since then. There are three bulbs in it. I'm going to go ahead and do a bulb count in the house for you: 4 in the downstairs bath, one in the mud room, 11 in the master bedroom, 1 in the stairwell, 3 in the living room, 3 in the dining room, 2 in the kitchen, 3 in the upstairs bath, 2 in the guest room, 3 in the library, and 3 in the computer room, for a grand total of 35 bulbs. 2-3 years. 9-ish dead bulbs. You do the math. Oh, and a good portion of my bulbs are on dimmer switches.
Oh, and the headaches? There's a reason I brought them up. You see, effective cost is a function of more than just monetary cost...
Mmhmm. And I have a friend who insists that as soon as she sees a CFL, she gets migraines. After getting evidence to the contrary (by virtue of how she didn't get migraines at my house, which she didn't know had CFLs), I secretly switched most of the bulbs in her house to modern CFLs while she was in the hospital (i.e., not the old flickery magnetic ballast ones) without her knowing about it to see if she'd notice. Guess what? It's over a month later, and she hasn't noticed. They're still there. Nor has she gotten a migraine (I'd know, because she calls us to take her to the hospital to get a shot when it happens).
She's hardly the only one I've had that experience with. I've had half a dozen people tell me that they can't stand CFLs who were shocked, when visiting my place, to learn (after being in my house for several hours) that all my bulbs are CFLs.
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Hard to dispose of? (Score:5, Funny)
Only if you have a conscience.
Speaking of conscience... (Score:5, Insightful)
Speaking of conscience, why is it that Slashdot is an oft-repeat offender in spreading anti-CFL nonsense? I've seen many pieces like this here.
If your utility has serious trouble with the power-factor of CFLs, they will tune the system with some additional inductance or capacitance. But they don't. Because this isn't a problem. It's the power factor for the sum of everything on the secondary of your local transformer that is a problem, and that probably ends up being close to 1.0 . Smart transformers, by the way, tune this automatically. I see them on more poles lately.
Second, the mercury issue. Which is 1/10 the mercury put out by burning hydrocarbons (especially coal) for powering incandescent lamps. Yes, the mercury from CFLs is mercury in your house, and the other kind of mercury from the generators powering incandescent lighting is just in the air you breathe in your house. And then, they take some time to start. This is a problem for some outdoor use, and tolerable for indoor use unless your home is really cold. And some of them burned out too fast, like any cheap electronics. Learn which brands don't.
It's nice that practical LEDs are coming some day. I'm sure we'll hear lots of propaganda about the arsenic and other toxic things in them, even though it's close to impossible to actually get those chemicals out of the chip, out of the plastic around the chip, etc., and they're in such small amounts that it doesn't matter anyway.
I only have one incandescent lamp left in my home, and that one is going to leave someday soon too. We are a healthy, happy family, and we're spending less and hurting the environment less. That's the reality for CFL users.
Bruce
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Re:Speaking of conscience... (Score:5, Informative)
Wow, I had no idea this would've been taken as an anti-CFL rant. Apparently neither my viewpoint nor the article's came through in the summary, which is more that there's no such thing as a free lunch (i.e. CFLs have downsides, too.). I think the headline was regrettably chosen, though, which I took from the original article and reworded to fit in /.'s character limits.
Bruce, you make a lot of good points. Yes, the mercury output is less than if you're on coal electricity (we're mostly hydro here). And unless lighting is the large majority of your electric bill (which it isn't for most households), the power factor of those CFLs aren't going to matter. I was surprised, however, to find that the power factor is as low as it is. I'll be happy once we have fewer integrated ballasts (which are produced as cheaply as possible). Spending an extra dollar on the ballast could improve the power factor and other issues significantly.
However, there's one claim that is problematic:
If you're using CFLs indiscriminately, you're applying the technology suboptimally. A rarely and briefly-used hallway light, for example, would be better served by an incandescent. The initial power surge to kick off the light will eat into your usage and savings -- very minutely, but still not the benefit you think you're getting. Which was really the point of submitting this article: we can't blindly use any technology -- CFLs, hybrid cars, wind power, etc. -- thinking that it's the perfect solution. Some thought has to be applied, and that requires information.
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Busted on Mythbusters (Score:5, Informative)
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Re:Speaking of conscience... (Score:5, Insightful)
Here is a good example of clean coal technology:
http://en.wikipedia.org/wiki/Kingston_Fossil_Plant_fly_ash_spill [wikipedia.org]
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Re:Speaking of conscience... (Score:5, Interesting)
And when a user drops a CFL, the problem is right there in their house, not miles away.
A CFL typically contains 3mg of mercury. A tuna steak is likely to contain as much as 1mg. If you eat fish three times and break a CFL once (and snort the mercury rather than disposing of it safely), you'll take in as much mercury from the fish as the broken lamp.
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Re:Speaking of conscience... (Score:5, Interesting)
Ok, here we go - someone check the math.
http://pubs.usgs.gov/fs/fs095-01/ [usgs.gov]
Tells me the mean amount of mercury in US coal is 0.17ppm.
We will assume 100% of said mercury enters the air.
We will also talk about 100 watt incandescent bulbs to make the math easier.
450 grams of coal are burned to deliver 1 KWh to your outlet.
http://www.amazon.com/Incandescent-Light-Shape-Frosted-100A19/dp/B000273TEA [amazon.com]
100 Watt bulb, 20,000 hours.
2,000 KWh in its lifetime.
900,000 grams of coal burned for this light bulb over its 20,000 hour lifetime.
153mg of mercury in said coal.
http://www.energystar.gov/ia/partners/promotions/change_light/downloads/Fact_Sheet_Mercury.pdf [energystar.gov]
tells me the average CFL has 4mg of mercury in it.
I was going to work out a full hour-by-hour comparison - but there is not need. I the case is B/W enough, unless someone can convince me less than 4% of mercury makes it up the stack.
Parent
But still... (Score:4, Interesting)
Oh Please (Score:5, Insightful)
Yes, they may consume more than they advertise, but they still consume half the power of the incandescent bulb they are replacing.
Re:Oh Please (Score:5, Funny)
The whole point is not the amount of power consumed by either bulb, but the fact that the profit-per-bulb for the utility companies is lower for CFLs than incandescent. This isn't about efficiency or conservation, its about the bottom line. Not only do CFLs use less power to begin with, some of what it does use isn't even billable. Its almost like stealing. I like it!
Parent
Summary is wrong. (Score:5, Insightful)
The utility does not have to *generate* the 28W of "real" power. It just
has to *transmit* it (and typically only from the local transformer to the
customer, since phase changes can be handled using capacitors when the voltage
is down-coverted the last time).
Re:Summary is wrong. (Score:5, Informative)
The utility does not have to *generate* the 28W of "real" power. It just
has to *transmit* it (and typically only from the local transformer to the
customer, since phase changes can be handled using capacitors when the voltage
is down-coverted the last time).
Sort of... the lower power factor means higher losses in transmission. So they don't have to generate the entire 28W, but they do have to generate more than the "apparent" load to compensate the additional loss in transmission.
Parent
Re:Summary is wrong. (Score:5, Informative)
That is correct, but it overstates the magnitude of the problem. If the PF is 50%, then the utility has to supply (transmit) twice the current. That extra current is not used up by the load, but it does translate into additional transmission losses.
T&D losses for the whole grid average about 10-15%. However, local T&D (from the substation) is much lower, because there is much less distance involved.
Let's conservatively say that the local T&D loss is 5%. Then the 13 watt bulb consumes 13 watts at the load. In addition, it is responsible for the dissipation of an additional 13 * 0.05 = 0.65 watts due to the additional line losses from the extra current being supplied.
So now your 13 watt bulb uses 13.65 watts.
Big.
Fraking.
Deal.
Nothing to see here. Please move along.
Parent
I'm still confused. (Score:5, Informative)
28 Watts of "Apparent Power" (CFL) versus 50-100 Watts of real power. (Incandescent) Help me understand how we are still not getting a net gain, and why I should care about this?
Is it:
A. I'm saving money at the expense of the power grid.
B. I'm still using at least 50% less wattage than I was before.
C. My lights never burn out anymore, and my only major worry is taking care not to break the reasonably tough bulbs since they contain mercury.
Re:I'm still confused. (Score:5, Insightful)
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Re:I'm still confused. (Score:5, Funny)
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Re:I'm still confused. (Score:5, Informative)
A. is true to some extent. The 28 VA will cause some losses on the net on top of the 13 watts you are billed for. But I doubt those losses are greater than maybe 1 or 2 watts. Disclaimer: I'm an electrical engineer by training, but don't work in the power grid business. So take this as an educated guess, not something I have calculated.
B. True. With the above estimate, make it 75% less or better.
C. Not entirely true, but good quality CFLs last pretty long. In my apartment, both the two 15 Watt CFLs I put in 8 years ago still work fine. A rather small sample but I think it gives you an idea of CFL durability.
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Idea (Score:5, Funny)
I think have a great idea as to how to solve this.
But unfortunately I'm still waiting for the CFL bulb above my head to light up.
So what. (Score:5, Insightful)
Arrgh! (Score:5, Informative)
As someone who teaches physics for a living, the Slashdot summary is making my eyes bleed.
Now EDN reports they may use more energy than claimed
Argh! No, they don't use more energy, but they do have higher "Load".
Here's the analogy. Every day, hundreds of thousands of people travel in to Boston. Does that mean we need to build hundreds of thousands of new apartments every day? No, because every day they all leave again: they're commuters.
Boston needs to design its roads to handle the rush hour traffic, but it doesn't have to build a ton of houses for them to stay.
Energy in a low power factor circuit is like a commuter: it flows into the device, then it flows back out again. The utility company needs to design its power lines to handle the rush hour flow, but you're not "using up" the energy in any sense.
TFA talks about real wasted energy caused by this "rush hour" flow, but transmission losses are a small fraction of total energy use. This isn't going to affect the overall efficiency of CFLs.
TFA talks about requiring "power factor regulation" on CF light bulbs. This is a pointless extra expense. While CF bulbs make life harder for the power company, other common appliances act to counterbalance the effect, so averaged over an entire city, the problem is mitigated. But even when it's not, the *power company* can always install devices (giant capacitor banks, typically) which compensate for the power factor. There's no need to build more power plants.
So what it comes down to is, CF light bulbs don't use more energy than they claim, but they do generate higher peak loads. We can force either the consumer or the power company to install equipment to compensate for this.
I say, "Hey power company. I'm paying you guys to deliver me some kilowatt-hours. Nothing in my contract limits how I suck up those kWh: if I do it in a way you're not expecting, it's your job to install equipment to handle it."
It's a LEADING power factor! (Score:5, Informative)
Mike Grather, of Lumenaire Testing Laboratory, 'checked the power factor for the CFLs and found they ranged from .45 to .50. Their "real" load was about twice that implied by their wattage.'
Oh, good grief!
It's a LEADING power factor, a load with a large CAPACITIVE component.
The main problem with electric grids is all the INDUCTIVE loads with a LAGGING power factor - like big induction motors. The power company has to hang capacitors (or other power-factor correctors, such as certain synchronous motors) all over the grid to "generate" the VARs that are "consumed" by the inductive loads. So until they're responsible for more reactive power than the motors, transformers, and such the compact fluorescents will be HELPING the power company.
Neglecting harmonics (which are a whole 'nother can of squiggles) the main issues for power transmission are:
- "Real Power" ("watts" = volts times amps) (current is in-phase with voltage).
- "Reactive power" ("VARs" {"volt-amps reactive"} = volts time reactive current) (current is 90 degrees out of phase with voltage, either "leading" or "lagging").
Cycle-by-cycle:
- Real Power generation must match consumption.
- Reactive Power "generation" (current into a load leading voltage) must match "consumption" (current into a load lagging voltage).
Whatever mismatch occurs in the field will be supplied by the generators and transmitted across the grid to the load. The Reactive Power (or "imaginary power" - because it's times sqrt(-1) when you use complex numbers to represent real and reactive at once) represents current thrown back-and-forth between capacitances and inductances. But when it gets transmitted on the lines or generated by a rotating machine it vector-sums with the real current, resulting in a higher current magnitude.
The losses in the lines and the generator and transformer coils are current-squared-times-resistance, and those are REAL energy losses that must be made up by the prime mover applying torque to the generator's shaft, regardless of the relative phases of the current and voltage. Also, the limit on transformer and generator capacity is heating due to current, so it's this vector-sum current that is the limit.
The power company would like to run their generators and lines as close to power factor 1 (all the current is in-phase) as possible, to get the most out of their equipment and to minimize the resistive losses that they have to make up for with fuel.
But most of the "reactive load" on the grid is induction from transformers and motors. So an inductive load is (arbitrarily) defined as "consuming" reactive power - thus defining a capacitive load as "generating" it. The power company buys and installs a lot of expensive capacitors (and switching equipment to turn them on and off as needed) all over the net, to "generate" much of the reactive power needs, making most regions as a whole close to resistive as possible and minimize VAR transmission and the resulting extra line losses.
The compact fluorescents will actually HELP this. Your neighborhood and its nearby business districts no doubt has far more inductive load (from normal fluorescents, arc lights, refrigerators, fans, blowers, compressors, etc.) than capacitive load (from switching power supplies, including those in compact fluorescent and electronic "balasts" for tube fluorescents). This will continue to be true even if ALL the lamps are replaced by CFs and electronic-ballasted fluorescents. So the reactive current from your CF lamps will flow only through a small amount of wiring before canceling out that from some inductor. This means they produce virtually no wiring loss. Indeed, it will likely keep VARs from motors from being sucked across more line resistance from a nearby pole-installation or substation's capacitors or over the long-haul grid from further away, for a net gain.
Re:That pretty bad (Score:5, Informative)
sure they are that bad. A CFL draws roughly half the power it emits as light (if you see what I mean) giving a power factor of about 0.5, which is dreadfully inefficient.
However, power factor refers to the current load, so a CFL of 0.5 will draw twice the current, but it will still be drawing the wattage it claims. So yes, they need to shove more current down the wires, but its costing you the rated watts.
Also, the CFL will be rated at 13W, the comparable IL at 60W. even if the CFL is drawing twice the current, its still using a quarter of the energy used by the incandescent.
Put it another way, a 60W incandescent draws 0.5 amps (60W/ 120V = 0.5). A 0.5 PF CFL at 13W draws 0.2 amps (13W/120/0.5)
I doubt its a serious blow against CFLs, just a serious attempt at FUD to talk up ILs, or an attempt to justify power companies charging you more (as that 13W lamp still costs you for 13W even if the power company has to deliver more).
Here's an less sensational article [iaeel.org] about the problem.
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Canadian Football League are terrorists!!! (Score:5, Funny)
ARGHH!
Those pesky Canadians causing trouble again, next they will try to burn down Washington...again. But I have news for them, the next time they try it, we will help them!
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