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Lifecycle Energy Costs of LED, CFL Bulbs Calculated
necro81 writes "The NY Times is reporting on a new study from Osram, a German lighting manufacturer, which has calculated the total lifecycle energy costs of three lightbulb technologies and found that both LEDs and CFLs use approximately 20% of the energy of incandescents over their lifetimes. While it is well known that the newer lighting technologies use a fraction of the energy of incandescents to produce the same amount of light, it has not been proven whether higher manufacturing energy costs kept the new lighting from offering a net gain. The study found that the manufacturing and distribution energy costs of all lightbulb technologies are only about 2% of their total lifetime energy cost — a tiny fraction of the energy used to produce light." The study uses the assumption that LEDs last 2.5 times longer than CFLs, and 25 times longer than incandescents.
I am practically a professional light-bulb changer, so I will say that in my non-scientific, non-measured, purely anecdotal experience, that CFLs put out a lot more heat than LEDs. Scads less than incandescents, but still, the ballast in the base of a CFL warms up quite a bit during operation, often growing too hot to touch when the glass spiral is still plenty cool. If you're concerned about minimizing heat, go LED.
I bought n-vision CFLs, which scored the highest in an objective, blind test done by popular mechanics a couple years ago. They were about $2 each with shipping, and have a 9 year warranty. So far, they've lived up to their promise : the light is almost EXACTLY like the light from an incandescent - low color temperature, lots of yellow, etc. They start up instantly, and of course use a fraction of the electricity.
Actually brand-name CFL's delivered to your door are a little over $1 each.
I doubt they use incandescent bulbs. High-pressure discharge lamps such as mercury vapor or metal halide bulbs perhaps. These are far more efficient that incandescent bulbs, although not as efficient as LEDs. If they have a yellow color, they will be low-pressure sodium or high-pressure sodium.
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As most household appliances are inductive loads and CFL's are capacitive, their 1 power factor actually improves the overall power factor of a home, so if anything, CFL's will slightly reduce the electric loses.
I feel like a parrot because I post this so often:
If you live in the UK don't buy CFLs. Phone your energy supplier and ask them how you can save electric. Mention you like the look of CFLs. They will send you a box for nothing. They will also send you one of these new-fangled LCD energy meters, if you ask. They just sent me enough roof insulation to cover the whole roof space, 270mm thick, for sixteen quid.
They have to do this. It is the law. A certain amount of profit has to be given away for energy saving measures. Everyone qualifies, not just new customers.
Yes, I work in the industry.
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LED lamps will almost certainly have the same thermal failure problems for precisely the same reason. Electronic circuits are simply not designed to operate at such high temperatures, and when you try to use them that way, they will fail much, much sooner than they ordinarily would.
Not to burst your bubble, but you know that LEDs are made from silicon and other semiconductors jut like MOSFETS and CPU's, right? They run at _very_ high temperatures - the max junction temperature of many MOSFETS can run as high as 175-200C!
This figure shows a Vfwd vs temp graph of an LED junction temp of 120C.
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Sorry, it sounds like you're just resistant to change.
On the subject of outdoor lighting, I started using CFLs in outdoor lights 15 years ago, precisely because the incandescent ones lasted so little time (requiring a ladder to replace, and the associated falling-off-a-ladder risk). At that time, it was the only place I was using CFLs. Even then, they lasted several times longer than incandescent bulbs and used a lot less energy - they had no trouble getting their rated lifetime. At that point we lived in a part of a country that regularly falls well below freezing during the winter. Cold was never a problem. The very same heat you say will break the lamp soon gets the tube warm.
LEDs are expected to become more energy efficient than CFL, so the heat "problem" (which I've never observed) would be even less. LEDs would be absolutely perfect in refrigerators - less heat emitted into the refrigerator which means less work to do for the refrigeration machinery. Since I have built my own LED lighting units from components, I can tell you that (a) they don't have many and (b) no electrolytic capacitors either, and (c) the temperature never gets near exceeding the rated maximum on any of the components at least for 3W Lumiled cool white Luxeon Rebels. The circuit consists of a current regulating power supply (purpose made for LED lighting) - basically a small 5 pin IC, some ceramic chip capacitors, a sense resistor, an inductor, and a schottky diode. Electrolytic capacitors are inappropriate for this small switch mode power supply, their ESR is too high. The power supply circuit for two 3W Rebels is about the size of a postage stamp even on a home-etched PCB. With a factory made PCB you could probably make it half the size without much difficulty.
LEDs are very commonly used for bicycle headlamps, they have almost totally displaced filament lights. I have a 3W LED front light for my bike. It is a sealed, self contained unit complete with battery, about 50% larger than a D-cell battery in each dimension, and will last over an hour off a charge at full brightness. No overheating problems.
The dimming of CFLs as they get old and fail is a much more graceful failure mode than sudden complete failure by an incandescent. It gives you more warning the lamp needs replacing, and doesn't leave you grovelling in the dark trying to replace a bulb when it fails just when it's inconvenient.
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Indeed. Most street lights are sodium vapor (sometimes mercury) vapor: http://en.wikipedia.org/wiki/Sodium_vapor_lamp
With the first link, the chain is forged.
Wikipedia says: "When used for heating a building on a mild day, a typical air-source heat pump has a COP of 3 - 4, whereas a typical electric resistance heater has a COP of 1.0."
So, yes, contrary to popular belief, resistive heating is a terrible waste. Burning the coal in a potbelly stove would be a little better then burning it in a power plant to generate electricity to transmit (with losses) over power lines to heat a wire near your ceiling. But using it to drive a refrigeration cycle would be a far better use of the energy.
Electric heat? In the US at least, natural gas costs about 1/3 of what electricity does per rendered BTU. Many homes have natural gas heating for this purpose, and deriving heat from electricity could be seen as only contributing 1/3 cost efficiency when considered to be a heat source. Not to mention summer cooling costs; are you suggesting swapping out incandescents for CFLs during the summer months? Interesting theory, I look forward to some math on the subject.
Oh please. First off, incandescents come in different color spectrums just like CFLs so just because the bulb is incadescent doesn't mean it's "good" light. Second, most of your time spent indoors is under flourescent light (work, restaurants, movie theaters) ergo shopping for work and night-time clothing is best done under flourescents.
You can get CFLs with a Power Factor of 90% or higher, so I call shenanagins. The capacative load increase of a CFL is completely negligible compared to the reduced active power consumption. I point to the fact my power utility is giving away CFLs by the dozen as evidence that power generation/distribution engineers find CFLs to be effective.
I have many CFLs in outdoor applications. I have a barn with 8 bulbs. The first year I put up 6 incandescents and 2 CFLs. My wife was afraid the CFLs wouldn't start up quickly enough so I put up 2 as a test.
In the first year 5 of the 6 incandescents died between our 100F summers and 20F winters. I replaced those 5 with CFLs that have continued to work for the last 2 years. Once my wife decided the CFLs provided good light in winter, I replaced that last incandescent.
Given that 3 of the bulbs are located 25ft off the ground, I really appreciate not having to change the bulbs annually.
I also replaced our two porch spotlights with outdoor CFLs. Yeah, they don't come up to full power immediately in cold weather but I upsized the bulbs. I went from 75W incandescents (950lumens) to 23W (1300 lumen) CFLs so I still have a hefty power savings and they start out almost as bright as the incandescents.
I've been on slashdot so long I'm starting to get out of touch with the cool stuff if it ain't on slashdot.