A 100 story tower needs to be compared against 6x15-story towers in terms of efficiency. What are the dis-economies of scale that apply to 100x story towers, b

A 100 story tower needs to be compared against 6x15-story towers in terms of efficiency. What are the dis-economies of scale that apply to 100x story towers, but not 6x 15 story towers? ------ The article discusses water pumping and sewage. But only water pumps seem to be inefficient (more power to pump water to floor 100 than to pump water 6x15 floors). Sewage benefits from oversized pipes. 6x sewage pipes are less efficient than one big pipe. Discussion of recycled grey water or even sewage recycling 'in the skyscraper' makes more sense with 100 floors rather than 15 floors. It's probably cheaper to have one big water recycling plant in the 100 story tower, rather than 6x water conditioning centers in 6x different towers.