TL;DR In Southern California should put PV on houses and buildings that are far from the coast, because coastal areas are cloudy much of the summer. But the actual pattern is the opposite. I estimate a 30% magnitude of loss. Even my employer, UCSD, has engaged in this foolishness in order to appear trendy.
Solar Industry Anxious Over Defective Panels – NYTimes.com.I had not solar panel quality was becoming such an acute issue “so soon.” Judging by this NYT article, many Chinese-branded PV panels are not reliable. This article sounds straight out of the book that Barry Naughton pointed me to, Poorly Made in China. The performance degradation data on well-made panels is pretty encouraging: 0.5% per year is typical, but the key is well made. There are many manufacturing shortcuts and quality problems that will lead to failure of electrical connections after a few thousand temperature cycles, for example. (Think night/day in Colorado!)
Power inverters, which are straight power semiconductor products, apparently may also be unreliable. https://www.greentechmedia.com/articles/read/3-Reasons-Why-Chinese-Solar-Inverters-Cost-Half-of-American-Inverters
It will be interesting to see what this problem with Chinese panels leads to in trade/market share. California and other states that subsidize PV should only pay for systems that pass good certification – for both performance and safety. For obvious reasons, testing long-lifetime behavior of electronics is very tricky.I wonder if we will see a repeat of the “solar water heating” fiasco of the 1980s, when lots of houses put pool heaters on their roof that started to leak and ended up getting ripped out. When the economics of a project are based on a 20 year life, and it only lasts 5 years, that is a colossal fail. If it catches on fire, as described in the NYT article, that is another situation entirely! What is the typical guarantee for homeowners in California?