How efficient is the average electric car?

I have read some articles about electric cars and their electric power supply. When you take into account the way that electricity is generated, how environmentally friendly and efficient is the average electric car?

If you take in the generation equation you have to factor in the efficiency of the power plant generating the electricity. NOTE: You cant use power rates because in many cases they are bent by business competition and government intervention.

Good question - I’m going to buy a watt hour meter and measure my monthly usage on my GEM to compare per mile. energy cost. I filled up my Avalanche yesterday for $1.94