A Second Look at Vertical Farms

Treehugger has devoted two posts to Gordon Graff's MA thesis designing what they call a "vertical farm."  Having been critical of past vertical farm enthusiasm, I have to admit this one looks more reasonable.  I'm mostly impressed by the fact there's no reliance on sunlight, but instead they rely on good old fluorescent bulbs, using a drum . Graff seems to have accounted for a lot of the costs and there's no claim for organic agriculture.    The biggest problem would be the economic justification: could a lettuce farm, that's what it grows, make as much money as uses of the same amount of capital applied to the same site?  (That's pointed out in the comments found on the second link.)