A number of people have written to Live Earth with concerns about the mercury contained in Compact Fluorescent Light Bulbs (CFLs). While this is a real concern when it comes to possible breakage of the bulbs and disposal at the end of their long, efficient life, it is important to remember that electricity generation from coal fired power-plants also releases mercury into the atmosphere.

When a full lifecycle analysis is performed, the mercury content in CFLs is still preferable to the mercury released from the additional electricity consumed by inefficient incandescent bulbs. (For the technical details, see the last paragraph).

From energy savings and greenhouse emissions perspectives, there is no comparison between CFLs and Incandescents – the CFL uses 60-75% less electricity for the same amount of light!!

For additional resources please visit the following sites.

- The Alliance for Climate protection: more on CFLs
- EPA Resources on Mercury in CFLs
- What to do if a CFL breaks
- Map to find CFL recycling in your area

On a similar note, others have written in asking why we are not promoting LED’s, or light-emitting diodes, instead of CFL’s. LEDs are a great technology just coming to market. They are even more energy efficient and long-lasting than CFL’s however their current initial cost is prohibitive – often over $100 for a single 100watt equivalent light bulb whereas a CFL is $3-12. For certain industrial applications where bulbs are difficult to reach and replace, it also makes sense, but it is beyond the reach of the majority of consumers. If you have the money to spend on LED’s, you may wish to experiment and be a very early adopter of this next-generation lighting technology.

On average, a U.S. kilowatt-hour generates .012 milligrams of mercury. So, a 20-watt CFL running for a (shorter than expected) lifetime of 10,000 hours would generate 2.4 mg of mercury, while a comparable 75-watt incandescent running for 10,000 hours (you would need more than one bulb, of course), would generate 9.0 mg. A big difference, as you can see. Add in the 5 mg of mercury that might reside in a CFL bulb (the high average I saw) and you get a total of 7.4 mg — still less than the incandescent.