http://www.jamesallenonf1.com/2011/07/f1-set-for-electric-starts-literally/
"F1 set for electric starts – literally!"
As the 2014 rules are written currently, we could have the opposite situation, with cars using electric only off the line and then the engine kicking in once the car is moving.
But this would lose all the shattering noise, power and thrill of 24 cars unleashing 750 horsepower, which is one of F1′s key signatures.