Can a 'smart grid' turn us on to energy efficiency?

There seem to be proof that cars are not the main source of CO2

According to research sponsored by the U.S. Government, improving the efficiency of the national electricity grid by 5 percent would be the equivalent of eliminating the fuel use and carbon emissions of 53 million cars.

so the entire electrical (note not gas) use is the rough equivalent of 1 billion cars.

The number of registered (and some are not used) cars in the US is 250 million.

So electricity produces 4 times as much CO2 as cars, and presumably gas produces similar amounts.

So forget changing that SUV to a Prius....