This graph shows a comparison of the kW hours output by the roof system and the tracker system. As you can see, more power is produced by following or "tracking" the sun all day long. Ideally, the more that the panels are perpendicular to rays of light coming from the sun, the more power that the panels produce. More photons are collected. In the summer, the sun is higher in the sky and therefore more photons get through the atmosphere because there is less atmosphere for them to pass through. This graph is for the time period of January 1 - the 13th week of this year with weeks ending on sunday. Week 1 was a partial week, starting on a wednesday and it was very cloudy, so there was essentially no power made.