electric trucks for in the city

This sounds really cool.

http://www.engadget.com/2007/12/07/smith-brings-worlds-largest-all-electric-truck-to-the-us/

Sigh. It could be cool, but our grid is just not ready for full electric vehicles. In fact, if the entire US nation switched to electric vehicles tomorrow, we'd be polluting 3x as much, and using far more water than we do today. Until the grid is transformed to use solely renewable sources of energy, any plug-in cars have to be considered a bad solution.

Hybrids, since they generate their own electricity, are a different story. They have an extremely positive impact on the greenhouse gas situation.

I haven't seen too many hybrid truck designs (I'm sure they're out there), but recently I came across these hybrid school buses that are being used in Lake Chelan that look pretty cool. Very expensive though:

http://www.autobloggreen.com/2008/03/14/chelan-school-district-happy-with-hybrid-bus/

While it is true that the current grid won't support it, I doubt that we're going to switch everything over in one year.  Or even ten years. 

Plus, with more and more people pushing power back onto the grid with solar/wind/micro-hydro/etc. ....  I think think that everything could work out with the existing grid.

It's an interesting argument. I think what you're saying is that if we forced all vehicles to convert to using the grid, we would then be able to just focus on getting the grid up to snuff.

The question then becomes what does that transformation look like?

One scenario is a de-centralized one in which individual households generate their own power and feed back into the grid.  You're right that rate of adoption here is increasing, but not remotely aggressively enough to make a significant difference. Something significant in the way of unheard-of government incentives or price reduction to make the technology more widely available would be required to kick the growth rate into the exponential levels.

The other scenario is a massive public-private joint venture to rebuild the grid in a centralized way. Something like Scientific American's "Grand Solar Plan" which takes 40 years, $150 billion dollars, but gets the entire nation completely running from Southwest solar power. There are a number of reasons why this is a more likely outcome, and more likely to be the path taken. In this case, the grid will need to transformed into a DC grid.

In either case, it's an interesting idea to mandate the leap to electric automobiles as a forcing function to transform the grid. But in either case, the grid transformation takes time, so we would increase co2 emissions significantly in the short term to attempt to force longterm benefits...