Vehicle to Grid (Score 3, Informative)

After we roll out the http://en.wikipedia.org/wiki/Vehicle-to-grid/ and http://en.wikipedia.org/wiki/Smart_grid/ and technology, then electric car owners will be able to sell their power back to the grid during peak usage to prevent blackouts, then recharge their car at night. Everyone wins - the owners electric bill is reduced, the utility avoids a blackout, and everyone else enjoys their AC. So - how many electric cars would it have taken to prevent the Enron blackouts?