(Swiss Federal Laboratories for Materials Science and Technology (EMPA)) In a new study, Empa researchers have investigated the ecobalances of various household light sources. In doing so not only did they take into account energy consumption, but also the manufacture and disposal processes. They also evaluated usage with different electrical power mixes. The clear winner is the compact fluorescent lamp, commonly known as the energy saving lamp.
They looked at incandescent, fluorescent, halogen and CFLs. They examined environmental costs to produce and dispose of as well as use.
CFLs won, partly, I think, because we would use 1/10 the number of bulbs as with incandescent . And, depending on how the energy is generated, they can result in much less carbon, mercury and other pollutants entering the environment.
I wonder how LEDs will turn out. Probably a little better than CFLs, I think.