Low Energy Light Bulbs Low Energy Light Bulbs - Your Contributions "Low Energy Light Bulbs - Savers or Wasters?" A special feature by Dave Mulligan

Cfls embedded energy, and more  Hi, nice article on cfls. I’ve long been highly skeptical of these things, for basically the same reasons  you state. However, I have a few comments, and a question. Any light bulb  would, it’s true, help heat a house in the winter, and this is apparently overlooked by its backers. However, the light bulb would only be approximately 100% efficient. Thus, if you are using an electric resistance heater in your home, the light bulb is just about the same efficiency. However, if you are using a heat pump, or a wood stove, for heat, this argument loses some of its power. My “geothermal” heat pump, for instance, has a COP of 3.95, so it’s giving me almost four times as much heat per watt of power consumed than my lightbulbs  are. I’m also very skeptical of claims that cfls last so much longer than incandescents. I built my house 11 years ago, and installed quite a few cfls (the ones I got free from people who don’t like the quality of the light, the half dozen given away by my power company, plus a few I got on sale at various places). I have lots of light bulbs in my home, an virtually all of them share a circuit with two or three other bulbs, controlled by one switch I installed all incandescent bulbs when I first moved in, Sept 9, 1997. A year or two later is when I began installing cfls.  Almost every  cfl happens to be turned on  simultaneously with one to three incandescent bulbs, just by chance, I suppose. But this set up did allow me to inadvertently witness the cfls’s longevity, as compared to incandescent bulbs. Every cfl in my home failed within  six or eight years, while not a single on of the incandescents failed, even though the incandescents were installed a year or two before the cfls! Now, if money is not the object, this is of little importance. But it leads  me to the question, which I’ve been unable to answer by searching rather diligently through the internet: How much embedded energy do cfls contain, compared to incandescents? In addition to the mercury issue, there is the matter of the energy required to keep replacing these cfls, which, at least in my neighborhood, have to be replaced more frequently, thus requiring a certain amount of energy use in their manufacture. Unfortunately, I have no idea how many hours either my incandescents nor my cfls last before dying, so I can’t make any projections as to how much embedded energy per kwh saved, but you get the idea. And I can’t say how much the cfls’ lifespan is reduced by switching on and off, though I am somewhat zealous about turning of unused lights. Oh, one other factor which supports using cfls: in summer time, in  an area where aircon is used, the aircon uses more electrical energy to overcome the heat generated by incandescents than cfls. Sorry this is getting so wordy, but I can’t help commenting on your statement “For this argument to work your electricity has to come from coal power stations. Gas, nuclear, and all so-called green generators do not release mercury. I believe this to be not entirely true, as many types of electrical generating plants are often cross connected thru “the grid”. Thus, using less hydropower (the main source of electricity in my area) can help reduce production of such things as smog,  CO2,  and mercury. At least that’s the way I see it; do you agree? Another big energy loss  with cfls is that required to drive our gas hogs to the local recycling center. Actually, there is no local recycling center where I live-not one that takes mercury. How much energy do you suppose is expended to “dispose of properly” these things? For now, at least, I’m sticking to incandescents, and waiting with bated breath for practical LED lights for my house. I trust you’re familiar with the potential benefits of LEDs? I just got to the section where you asked about embedded energy, and see that I’m not the only one who’s frustrated by lack of information on this subject. I’m not sure, but I suspect that the energy used in disposing of  cfls could be considered part of the embedded energy, no? Oregon, USA, May 2007 Back to Top

Bulbs and energy Dear Dave I enjoyed your page about CFLs. I am trying to find out the embodied energy (manufacture) of a CFL for the book I am writing. (http://www.withouthotair.com/) You might enjoy my book. It's similar to your page - trying to say "cut the bullshit, let's talk facts". I don't think it's likely that the embedded energy of a CFL is as big as the energy it consumes during use.  (Based on the embedded energy of  other things like computers and cars.) I have two suggestions for your page. 1) in your list of things      Don't go on holiday - Don't travel - Live next to where you work and walk to it - Don't drive a 4x4 - Don't fly - Ration electricity, gas, petrol, etc. - Charge a realistic price for petrol - at least twice its current price - Only use public transport - Send your children to the nearest school - Walk to your local shops (and take a shopping bag) I suggest you should include "TURN THE THERMOSTAT DOWN" since this is probably the single best thing a Brit can do. 2) I suggest changing the font and background as (for me on my screen) skinny white letters on black background are pretty hard to read. Finally, it's not scientific, but I am measuring the hell out of my  house now. http://www.inference.phy.cam.ac.uk/sustainable/images/newgas.png http://www.inference.phy.cam.ac.uk/sustainable/images/newelec.png Turning the thermostat down is the winning act, by my measurements! David J.C. MacKay, October 2007 Back to Top