Wall St Journal 
Thursday, Oct 2, 2008
The law of unintended consquences strikes again—this time with light bulbs.
A new study published today  in the journal Environmental Science and Technology (sub reqd.) concludes that the shift away from old, incandescent light bulbs to more-efficient compact fluorescent bulbs carries plenty of environmental trade-offs.
The upshot: Making the switch is an environmental win for states and countries that generate most of their power from coal, because the more efficient bulbs mean less electricity generation, and thus fewer emissions of mercury into the atmosphere. But for places that don’t rely on coal power, the shift toward CFLs will probably mean more mercury pollution. That’s because of the mercury content in the fluorescent bulbs themselves.
Plenty of countries, from the U.S. to Australia, are trying to phase out the century-old lightbulb in favor of flourescents that use less power and last a lot longer. The 2007 energy bill in the U.S., for instance, will ban most incandescent bulbs by 2014, prompting big manufacturers like General Electric to switch gears. But not all countries (or states) stand to benefit equally; some will actually take a step backward, environmentally.
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“Compact fluorescent lighting is an area where we’re really pushing this alternative and all these policies are being enacted, but we’re not looking at the potential unintended consequences of what we’re doing,” said Julie Beth Zimmerman, an assistant professor in Yale University’s Department of Chemical Engineering and a co-author of the paper.
Among the potential losers? California, an early pioneer in banning old-fashioned bulbs. That’s because California gets very little of its electricity from coal. Other regions that can expect to see more pollution, according to the study, are South America, Africa, the Middle East, and Scandinavia.
On the other hand, coal-intensive regions such as China and Central Europe stand to reap huge benefits from making the switch, the study finds.
Now, all policy makers have to do is find a way to convince consumers to shoulder the upfront costs of buying the more expensive bulbs.