Re: Compact Fluorescent Light Bulbs – Bad math

I'm sorry, but your calculations are simply wrong.

Your conclusion is that if a CFL gets used for 50 hours, it's paid for itself versus a comparable incandescent bulb. However, your calculations for establishing that metric are based on a fixed relationship between the lifetime of a CFL and that of an incandescent bulb: you say that the lifetime of a CFL is 8 times that of an incandescent bulb. If the CFL lasts only 50 hours, then that fixed relationship, itself, is wrong, and the cost factors used to compare the two types of bulbs are meaningless.

What we need instead is a fixed-cost factor for producing and disposing each type of bulb, and a statistical distribution of the ACTUAL lifetimes of a large enough number of bulbs to verify the lifetime figures. Only then will we have a useful metric for comparing the bulbs, a metric showing actual production/disposal costs per lighting-hour. I suspect that that analysis would not be so wildly in the CFL's favor.

I believe the DOE's figures for energy savings from CFL are also inflated. Residential use accounts for about 1/3 of our nationwide electrical use (see http://www.eia.doe.gov/emeu/aer/), and barely 9% of the average home's electricity gets used for lighting (see http://www.eia.doe.gov/emeu/recs/recs2001/enduse2001/enduse2001.html.) That means that at most, 3.3% of the nation's retail sales of electricity gets used for residential lighting. If CFLs genuinely use 1/4 the energy of incandescents, and ALL lighting gains that level of improvement, the net will be a 2.4% reduction in total national electrical sales. Note that this excludes all non-electrical energy usage; we're only talking about electric power generation. Note that the figure for residential electrical use allocates standard electrical generation and transmission losses to the residential sector, which skews the numbers way up. And note that the reduction of electrical use for lighting to 1/4 of current usage is wildly optimistic; not all current lighting is incandescent, and consumers report that you can't really replace incandescents for CFLs one-for-one.

Short version: switching from incandescents to CFLS won't make much difference.