Tracking Systems

Tracking systems are hardware devices usually used on pole mounted solar arrays to allow the positioning of the solar panels to follow the movement of the sun.  This helps ensure that there is maximum exposure for the solar cells.  A tracking system can increase the output of your PV system by up to 30% in the summer and 15% in the winter over non-tracked systems.

Tracking systems are usually classified as being either passive or active. In a passive system the tracker follows the sun from east to west without using any type of electric motor to power the movement. Instead the system rotates from a combination of heat and gravity.  Because no external source of electricity is needed such systems are ideal for remote off-the-grid scenarios or use with water pumping systems where peak the peak demand is in the summer.

Tracking systems are also sometimes classified as to the number of axis they track against.  Simple one axis systems rotate only left to right rather than in an arch.  A two axis tracking system will track both left to right and up and down.  This allows it more accurately to follow the true arch of the sun throughout the day.

Passive tracking systems have some limitations.  First, they are somewhat susceptible to high winds which can throw the tracker off the proper direction.  They can also be somewhat sluggish in getting moving in cold temperatures because they are mechanically rather than electronically driven.

Active tracking systems are powered by small electric motors and require some type of control module to direct them. They are similar in approach to the systems supporting giant TV dishes.  Active systems require some electric power which can come from an external source or from the solar panels themselves depending upon the model.

The big question with trackers is whether or not the additional cost, of a tracking system, both initial cost and maintenance cost, is justified by the additional electric power they generate.  Tracking systems require maintenance and add a good bit of complexity to the system simply because they have moving parts. EB has reviewed the literature on this topic and the general consensus seems to be that tracking is probably not necessary or advantageous for most homeowners.  In most cases simply adding another solar panel or two will provide just as much an increase in output with far less cost and hassle.