In the midst of rereading, my book Build Your Own Electric Vehicle 2nd Edition, I thought (after looking back) at the whole book that I really like the section in chapter two where we talk about how electric vehicles can help with the environment and energy.

Electric vehicles generate no emissions and reduce our reliance on imported oils.  Frankly, until you get to an appreciable number of electric cars on the road today (hundreds of thousands to millions), they do not impact emissions from electrical power plants.

Just as equally important are maintaining stringer toxix air pollution emission levels along with conforming to increasingly higher mandated corporate average fuel economy (CAFE) levels puts an emourmous burden on gas engine technologies and your wallet / pocketbook.

To quote Quarlu Wang, Mark A. Deluci and Dan Sperling, who studies the subject extensively stated:

California and the US adding electric cars to the road will reduce CO2, hydrocarbons and to a lesser extent, nitrogen oxide emissions. 

As for the argument about coal being 100% of the fuel is not true.  The majority of fuel in this country is coal for powerplants; however natural gas and NOW a more ever increasing renewable energy portfolio and nucular (sorry nuclear) too.  In addition, shifting the burden to coal-powered electrical generating plants for electric vehicle electricity production has these effects: