SolarCity politely disagrees with APS and First Solar.
In First Solar’s recent defense of Arizona Public Service, it echoed the utility’s claim that utility-scale solar is the least-cost solar option. But is utility-scale solar really cheaper than distributed rooftop solar? In a June op-ed, First Solar CEO James Hughes contended that APS is “right to seek the highest volume of solar power at the lowest cost to rate-paying customers,” adding that “the cost per installed watt of utility-scale systems is as little as one-third that of rooftop systems. . . .
http://www.greentechmedia.com/articles/read/Is-Utility-Scale-Solar-Really-Cheaper-Than-Rooftop-Solar