My guess is that no batteries are involved and that the panels will simply feed into the electrical grid and the grid will need all that can be supplied at any given moment and there will be a net reduction of fossil fuel needed when the sun is out. The statement that 400 homes or 1000 homes or whatever can be powered by the panels is simply one of SCALE....comparing the output in Kilowatts for the panels to the # of KW's that the average house uses. (Divide this number by 22 to get the number of Al Gore houses that would be powered by the panels!)
