Solar PV Tracker or No PV Solar Tracker
When investing is a PV system customer occasionally ask about solar trackers. A solar tracking system is a device that optimizes the angle orientation of the solar array towards the sun. Solar Tracker are usually meant for ground mounting systems. With flush mounts solar roof racks, the angle of the installation is usually the same as the angle of the roof and as such no adjustment is made.
There are two types of tracking systems. The first and most basic is a tracking system that adjusts the array horizontally up or down. This is known as a single axis tracker. This is used to maximize the seasonal positioning of the sun. In the winter the Sun is 30 degrees lower than in the summer so by changing the angle to a more vertical angle you can get a more perpendicular positioning of the solar array. In the summer the sun is higher in the sky and a lower panel angle will provide a more perpendicular direction versus the sun’s rays.
This type of seasonal tracker is usually a manual tracking system such as found in our ground mount Titan solar tracking system. The entire array is usually adjusted a couple times a year to maximize the solar array. Because this type of adjustment is usually manual, there is very little that can break or go wrong with the system. In this way a seasonal adjustment is a good investment when purchasing a ground mount system.
The second type of solar tracking system is known as an XY tracker or dual axis tracker. This type of tracker not only adjust horizontally to the sun’s angle but also swing vertically to follow the sun in the sky as it rises in the east and sets in the west. Most of these tracking systems have a special solar eye that senses the suns strongest location and through motorized actuators, moves the solar array into the optimal position both vertically and horizontally. Most of these types of system claim to be able to increase the solar array’s performance by 20-30% as the array is always optimally facing the sun at the most perpendicular angle.
Should you invest in a tracker? This a question that is often debated! For residential use the general answer is YES if you are using a ground mount for seasonal efficiency but NO for upgrading to a dual Axis XY tracker. The reason is that a dual axis tracker is often very expensive to install given the wind loads it must be able to support and the motorized turning mechanism and electronics that are required. The initial investment can increase the cost of a solar array by 30-40% reducing the overall return. The other problem is that the motorized tracker and internal electronics will ultimately fail and require replacement over time. NO tracking system comes with a 25-year warranty that can match the Enphase inverters and the solar panels. This reduces the oval return of the investment by shortening it lifespan. Instead of 25 years of maintenance free energy you will now need to budget periodic tracking repairs.
Yes trackers do increase the efficiency of the array, however with the high installation cost and the added capital cost, we recommend you simply increase the size of the array and have the same added energy output that you would have gained from a tracking system without any future repair costs.
Let’s take an example. A 3 Kw solar PV System cost $9,000 installed. A dual axis tracking system cost and additional $3,000 plus an additional $2000 for installation (large concrete base required). So, this brings the cost to $14,000. With this tracker the expected return is 1/3 extra which brings the system to an effective 4 Kw output. However, the customer can buy an additional 1/3 extra energy production by adding 4 more 250-Watt panels at a cost of say $3,000 installed. Now not only is the customer ahead financially ($12,000 versus $14,000) but the customer also now has full 25-year warranty on his investment without any risk of mechanical failures.