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CFLs Causing Utility Woes
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."
Since I have switched to CFL... none of my light bulbs has ever burned out yet for 9+ months. With incandescents, I was changing 5-6 light-bulbs a month (I live in an older house, the electric grid and the wiring in the place I live is not always ideal for traditional light bulbs)
Only if you have a conscience.
Yes, they may consume more than they advertise, but they still consume half the power of the incandescent bulb they are replacing.
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).
The
It's been a while since I was in electrical theory classes, but doesn't a 13 watt CFL lamp consuming 28VA of power still consume less power than a 60W incandescent bulb?
28W less than 60W ??? I would hope so or I need to start studying new math.
greed@All_Evils:~#
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.
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.
There's no -1 for "I don't get it."
If the customer is only billed for the 13 "real" watts used per the summary, then this is a non-issue. I paid for a 13 watt bulb advertising $x in saving on my electric bill, and I get $x in saving on my electric bill. I make my purchasing decisions based on the cost to me, not on the cost to the power company.
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 about the problem.
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."
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.
Some drink at the fountain of knowledge. Others just gargle.
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!
Down With Slashdot BETA!!! I've been around the corner and seen the oliphant; you can only abuse me from your perspecti
While a little more expensive they last even longer (20 years?). They really aren't available much greater than 40 watt replacements but I've been happy with the performance. Not effected by cold and come on instantly.
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.
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)?
"99 dead duelists of Dios on the wall. 99 dead duelists of Dios! Take one's ring, pass it around..."
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
Bruce Perens.
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.
Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way
This was "busted" by MythBusters: http://kwc.org/mythbusters/2006/12/episode_69_22000_foot_fall_lig.html And another article from Lawrence Berkeley: http://enduse.lbl.gov/info/LBNL-45862.pdf (scroll down to myth #3).