"Mike Scott" wrote in message
...
I'm curious. "Low energy" bulbs are very much in the news - but how much
extra energy is expended in their manufacture compared to a standard
incandescent? I assume it's more - so is there a real net /overall/ saving
over the bulb life? If so, how much?

I've not got any figures, but taking the worst case conditions

Costs will break down into 3 components
Material costs (cost of raw materials) Assume = zero
Assembly costs (cost of getting people to put them together) Assume = zero
Energy costs (what you are asking about).

In China energy costs are about 1/3 of ours*, so given that UK retailers can
sell at bulbs at £1 we can set an upper limit for the energy cost of 30KWh
per bulb in China . We also assume that the manufacturer, importer and
retailer are all selling the bulb at cost price.

If we compare 6000 hours of CFL useage at 25W with 6000 hours of GLS at
100W, we get an energy useage of
150 KWh for the CFL and 600KWh for the GLS

Assuming the very worst case (that the GLS bulb had absolutely no energy
cost at all), we can see that there is still a 420KWh lifetime benefit per
bulb. (70% reduction in electricity saving)




Cost of Electricity in China
* http://www.chinadaily.com.cn/bizchin...ent_585299.htm