For Those Who Worried About Embedded Energy
We've known for a while that LED is probably the future of lighting (or maybe OLED). Most of the LED bulbs that are on sale these days aren't quite there yet - not quite the right color, not quite bright enough, a bit too directional - but progress is being made and within a few years we should be seeing a faster transition, kind of like what we saw when CFLs reached a certain price/quality point a few years ago. But some LED skeptics were saying that it took a lot of energy to make LEDs, and that this could be their Achilles' heel when compared to incandescents. The German company Osram looked into that argument, and the numbers are reassuring.
They found that only about 2% of the total life-cycle energy used by a LED bulb will be used during its manufacturing. If you compare it to an incandescent bulb, that's about 1/5 of the total life-cycle energy, a very significant saving:
25 light bulbs with 40 W each have a lifetime (all in total) of 25,000 hours. During that life they need 1,000 kWh of energy. With today´s prices* this means he has to buy 25 bulbs for around 25 € and to pay 210 € for the energy. Additionally the bulbs emit nearly 500* kg of CO2 in the atmosphere.
One single OSRAM Parathom LED light source is needed for the same lifetime of 25,000 hours. But it needs only 8 W - that means only 200 kWh over the whole time. And it emits only 100 kg CO2 at a price of 40 €.
The study's methodology was ISO 14040/44 and the results were certified by three university professors in Denmark and Germany as adhering to the standard, so despite the fact that Osram isn't exactly an independent observer (they make LEDs), it seems like a trustworthy study.
The only problem I could find with the study is that they compare to 40W incandescents. That's because Osram doesn't yet have commercially available LED bulbs that produce as much light as a 60W or 100W incandescent. But the results should scale. Now we just have to wait for brighter LEDs...
For more, check out: LED vs. CFL: Life-Cycle Study Shows a Close Race, but LED Likely to Take the Lead
Via Osram, NYT
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