Capacity factor in Arizona is 25%, not 20%. More importantly, the fact that solar works only part of the time *is already accounted for* in these numbers. Otherwise, capital cost of PV would be $13000/kW, way above everything else, and new solar installations in 2016 would not be the largest segment among all new power plants. Business disagrees with you. Solar power plants are popping all over US southern deserts, faster every year. At the same time, Westinghouse, which constructs all new nuclear plants in US (four AP1000 units) ran into large cost overruns and filed for bankruptcy in March of 2017.