The largest is on one of its other theaters. Solar promoters consider themselves part of a political movement to save the planet. They do not tolerate naysayers. That is why it is still so easy to find stories that say the non-performance of solar equipment "really looks like a non-story." That is what one analyst said after First Solar's stock recently took a 10% hit in one day after the company revealed problems with its products. Here's a bonus reason No. 4: Shade. A shadow on a solar array not only knocks out power to that panel, it also shuts down a wide area of panels around it. Listen to the National Renewable Energy Laboratories: "the reduction in power from shading half of one cell is equivalent to removing a cell active area 36 times the shadow's actual size." Do your own test: Ask your neighbors if they know how shadows hurt solar panels. Most do not. Some companies install monitors on each panel. But monitor makers find that the very existence of their product is an admission of problems in that industry. And that is the last thing the True Believers want anyone to hear about. Especially investors. That is why I shorted First Solar at $121 in March of 2011 -- and said so on my radio show and in my newsletter. And that is why investors should stay away from betting on their resurgence. This article is commentary by an independent contributor, separate from TheStreet's regular news coverage.