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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."
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 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.
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.
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.
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..."
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.
"99 dead duelists of Dios on the wall. 99 dead duelists of Dios! Take one's ring, pass it around..."
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.
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?
"99 dead duelists of Dios on the wall. 99 dead duelists of Dios! Take one's ring, pass it around..."
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
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?
"99 dead duelists of Dios on the wall. 99 dead duelists of Dios! Take one's ring, pass it around..."