PLUG-IN POLLUTION
The expected introduction of plug-in hybrid electric vehicles could cut U.S. gasoline use but could also increase air pollution in some areas. A plug-in's lower tailpipe emissions may be offset by smokestack emissions from the utility plants supplying electricity to recharge the big batteries that allow plug-ins to run up to 40 miles without kicking on their gasoline engines. Plug-ins, called PHEVs, are partly powered by the fuel used to generate the electricity. (USA Today 2/26/08)