Elon Musk is the CEO of Tesla Motors. I saw a youtube show http://vodpod.com/watch/1506024-why-tesla-motors-trashed-plug-in-hybrids-idea where he talks about the volt getting under powered when the engine comes on. My understanding and everything I can read about the Volt is that it only the electric motor supplies power to the wheels. The engines only purpose is to charge the batteries.
Now instead of having the fixed range of the batteries you can extend the range by re-charging the batteries as you drive.
Mr. Musk comes off as un-informed. The generator means you have more weight, you have to figure out how to get the fuel system working and all the other components, he has valid points.
For the average consumer you need to have a way to increase the range of an electric car. Most people can not afford the price of a full electric vehicle that will perform at freeway speeds, but they can not go on a vacation with it because they have to stop every 100 miles to charge overnight.