In the early solar PV days, trackers were a necessity to maximize the energy output from very expensive solar modules. Unfortunately, in those days trackers were mechanically complex and unreliable (remember TV antenna rotors?), and the control systems were expensive and finicky. As solar module pricing declined, the interest in trackers for small systems began to wane.
via Renewable Energy News – RenewableEnergyWorld.com http://ift.tt/VHUO5q