Many of you already know of my skepticism of compact fluorescent lightbulbs. Now utilities are joining in the hate: CFLs use about twice as much energy than previously claimed.

Lightbulbs, TVs, ovens, baseboard heaters—whatever—draw energy from alternating current with varying degrees of efficiency, due to the funkiness of alternating current.

Allow me to explain, by taking us all bowling. Kinda.

We want to pump up a tire with a foot bicycle pump down on the far end of the bowling lane. We screw the pump down on its side, and aim with our bowling ball. We hit it, and it shatters into pieces. No good. Marbles would be safe for the pump, but getting them all the way down the alley is next to impossible. They slow down and stop due to friction almost immediately, where the heavy bowling balls have enough momentum to make it all the way to the end. Now what?

We get a clever idea: Let’s line up a whole bunch of bowling balls in the gutter, placing the last one on the handle of the pump. On our side of the lane, we put a spring on the end of the line of bowling balls. We pull back our spring, a little bit, with the first ball and then let it go. The energy is transferred to the far end through each ball. The last ball at the end of the line presses down on the handle. Some of the energy transferred goes to pump up our tire; the rest goes to compress the pump’s spring. Eventually, the pump spring gives back most of this stored energy, sending the bowling balls back to our spring. Since some of the energy was used up, we pull our spring back a bit more, and release it again. We now have waves of energy successfully transmitting from our end of the lane to the pump’s end: Alternating current.

(If this doesn’t make sense to you, you should feel really thankful for Nikola Tesla. Without his genius, you would be cold and hungry right now.)

What the power company is doing is constantly adding energy back into the spring at their end of the chain of bowling balls (electrons, unpacking our metaphor). A/C devices with a perfect power factor of 1.0 act as perfect springs: all of the leftover energy delivered is returned in phase back to the power plant. Compact fluorescent lightbulbs mess up the line of bowling balls like an obnoxious kid. When the wave is outgoing, they push in on the chain a little bit; when incoming, they push outward. CFLs make a portion of the alternating current go out of phase. The bowling ball waves still work, but it takes the power company more effort to keep each wave going.

About half the energy used up by a CFL goes to this naughty out of phase game. While there are ways of designing well-behaved CFLs, most companies making them (typically in China, with factory workers twisting hot glass filled with mercury powder by hand) don’t exactly seem interested. As per Better Off Ted, the corporate motto is, “Money before people. It’s engraved right there in the lobby floor. It just looks more heroic in Latin.”

Jonathan Golob is an actual doctor.

37 replies on “Yet Another Reason to Dislike CFLs: Horrible Power Factors”

  1. I never liked ’em either. They cost too much, I hate the mercury in them and they take FOREVER to get bright. They also have a tendency to overheat and burn up in covered fixtures. Hey – the guy that invented them doesn’t even like them!

  3. Aren’t they marketed as, like, four times more efficient than incandescents? So with these findings, they’re just twice as efficient. Still better. And they still last longer, right?

  4. mercury – recent science tells us so much more deadly than ever before perceived

    and the Greens and City think these will ALL be correctly recycled after tens of millions are in households

    wrong

    and, it, mercury collects in fish and shellfish, yuk

  5. Since florescents become law of the land here in CA, you really can’t find any decent selection on incandescent bulbs outside of a large hardware store. I’ve got three 20 watt incandescent bulbs in my bedroom, and I’ve changed each of them once in 2.5 years. So either I’ve got some serious Temple of Jerusalem magic happening in there, or some people just spend way too much time at home with the lights blazing.

    I’m not sure what my point is. Oh yeah; florescent, still not sexy. And apparently, not as efficient as they should be either?

  7. @4 Even if we burn all of them in the open air there is still a net reduction of mercury output because power production, thanks coal, emits a lot of mercury.

  9. They aren’t perfect but they are still much more efficient than incandescent. The Mercury levels are fairly insignificant. This being said they aren’t perfect. Make way for LEDs, the technology is on the cusp of changing the world forever.

  11. Out of curiosity, does the bowling-balls-lined-up-in-the-gutter metaphor make sense to any of you?

    This is one of the hardest things to explain to people who don’t love cosine.

  14. Nice try explaining power factor to non-techies, Jonathan. I’m an electrical engineer and still find it to be a prickly concept. The hard part is explaining why more power capacity is required when voltage and current are out of phase. I like to think about it in terms of reactive power, but that doesn’t really have much in the way of real world meaning. Best of luck.

  15. Jonathan — I get the gist of it, but I’ll admit that a) I had to read it through a couple times and b) I’m not 100% clear on how literal the metaphor is — do the electrons sit there basically static and “bump” back and forth?

  16. @10 Thank you for being the first to have said it.

    LED’s people. CFL’s will go the way of the cassette tape.

    The problem is, when CFL’s go away, they won’t REALLY go anywhere except landfills where they’ll leak mercury into the water table. You’re welcome, kids of the 21st century.

    Of all the shortcomings of CFL’s, I’d hardly consider the power factor to be an issue, when compared to overall power consumption of incandescents.

  18. Stop whining and buy more efficient LEDs instead.

    Besides, those rope lights and sparkle lights look way cooler and last about 20 years or so, and don’t interfere with remote controls.

  19. Speaking of Florescent bulbs and electricity, here is an art installation involving a field of florescent bulbs powered entirely by the electric field generated from overhead powerlines.

    http://io9.com/5204842/a-field-of-light-…

    Makes me think that all those crazy people worried about living under powerlines weren’t so crazy after all…

  20. Only the latest chapter of the “Al Gore Green Hysteria Global Warming Scam” to be debunked.

  23. Did you read the thread on slashdot about this? The anti-CFL arguments are basically FUD, overblown and/or bogus according to most of the physicists and electrical engineers who responded in the comments. Here’s a link: http://hardware.slashdot.org/article.pl?…

    In short: CFLs do not use twice as much energy as previously claimed, the mercury issues are not at all significant (esp. compared to other sources of mercury like coal plants) and the functionality problems are mostly long-since-solved issues.

    Frankly, CFL/LED “skeptics” are about as scientific and useful as climate change deniers (or ID proponents) these days (Or, to risk Godwining-myself, Holocaust deniers). There’s always some tiny bit of new “evidence” that can be twisted to “prove” their skepticism was warranted, but under scrutiny, the evidence never holds up. Despite that, the deniers march on, or blame a conspiracy, or whatever.

  24. @23
    Jonathan just said they use twice as much electricity as claimed. Watch yourself or you might be banned from slog.

  25. Wow. Stick to biology.

    Wanna try doing this again, but with numbers? Specifically, please prove the “twice as much energy claim.”

    Hand-wavy barely-applicable analogies will receive no credit.

  27. There are some compelling arguments for and against CFL. Much of it has to do with the compromises that have been made to save cost in order to make CFLs viable. CFLs are much more complicated to manufacture as well as incandescents, and if manufactured poorly, they will defeat all of the advantages that the technology can provide under ideal circumstances.

    Although the technology in theory offers an advantage, its increased complexity makes it more difficult to approach the ideal.

    To me, the problem of mercury waste disposal disqualifies CFLs as a long term solution. LEDs are more efficient, last longer, and do not have the same potential to expose people to hazardous materials.

  31. @23
    Who’s doing the denying? Mercury issue insignificant? Not when you have millions of CFL’s laying around. And no, the functionality problems have not been solved, if anything, due to poor quality control, they’re worse. Why can’t you just admit they are crap instead of vilifying people who don’t want to use them?

  33. My main beef with the CFL push is that they do not, in my experience, last significantly longer than incandescent halogen bulbs (Philips Halogena and the like) while being undimmable. As I don’t usually run my lights at full brightness, the power savings of CFL are negligible. I have begun an attrition program in my home to revert to halogen lamps as the CFLs fail; I’m down to my last 2 (of 8 purchased last year, of at least 3 different brands.)

    Ignoring the light quality, which I was willing to overlook to a degree, the manufacturing quality clearly sucks. Corners have been cut and the bulbs simply do not last their advertised lifespan, even in open fixtures.

  34. I see no comparative numbers here, so I’m forced to conclude that this judgment is based on “ick factor”. Gimme the numbers, scientist!

  36. AC is not used for power transmission because it’s more efficient. In fact, AC power transmission is inherently less efficient than DC, due to the “skin effect.” Rather, transmission lines use AC because AC can be easily converted from one voltage level to another.

    Transmission efficiency over long distances is primarily a function of voltage: the higher, the better. Until very recently, the only practical way to “step up” to high voltage was through a transformer, and transformers require AC to operate.

    But modern electronics now allow for efficient and inexpensive DC-to-DC voltage conversion. DC transmission lines are not common yet, but they will eventually come to displace AC lines entirely.

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