Consider the advantage of such greenhouses:
1. Highly-controlled growing environments, which means just about eliminating the need for pesticides and herbicides, not to mention being able to grow vegetables essentially year-round.
2. Very efficient water use, thanks to these greenhouses using hydroponics.
3. Because they can be located in urban areas, it means very low transportation costs and much higher quality of freshness of produce grown when finally sold at the retail level.
In short, we can effectively have farm-fresh produce of many types essentially year-round.
World’s Largest Indoor Farm is 100 Times More Productive
http://www.freerepublic.com/focus/f-bloggers/3246076/posts