Recently I have noticed that there has been a significant increase in interest in solar trackers. I would like to take some time here to discuss a few of the advantages and disadvantages of this type of system. Solar module tracking systems are a type of mechanical racking that typically utilize motorized components. The goal is to maximize the amount of energy that is collected by the arrays during the day. Traditionally fixed racking, which does not actively track the Sun’s path across the sky, can have less harvesting potential due to lower sun angles or back shading from other arrays in the system. To address this potential problem and to maximize the total system output, solar trackers automatically adjust through the day to follow the Sun’s movement across the sky.
Sounds like a no-brainer? There are certainly a few things you should know before deciding to opt for a tracker over the fixed mounted solutions.
First some of the advantages:
- Solar trackers generate more electricity in roughly the same amount of space needed for fixed tilt systems, making them ideal optimizing land usage. This could be a very good rational for going with a tracker if the project’s available space has some restrictions.
- There are two basic types of solar trackers. Single-axis trackers, as the name implies, will follow the movement of the Sun in one direction. Then there are dual-axis trackers, which have the additional benefit of being able to tilt the array at the optimal angle as the Sun moves in the sky.
The disadvantages:
- Tracking systems are going to be more expensive than the opposing fixed mounted variety. This is largely due to having motorized and moving parts. Which leads way to another disadvantage.
- Maintenance: Having all these moving, mechanical parts means that there will be some amount of regular inspection, adjustments or even replacements required. They are not exactly “set and forget”.
In short, a solar tracking system may be the right fit for your project due to the benefits of capturing more energy that a fixed mount and by extension the ability to due this in the same foot-print as a fixed rack. However, it is best to evaluate those disadvantages to determine if the extra cost and on-going maintenance will not overshadow the value of the potential gains of the system.
Comments
It is not obvious that sun trackibg gives you more output from the same area of land. The array geometry that maximizes the amount of energy collected from a given land area is a fixed array of horizontal panels covering tje whole surface with no gaps. That cillects all the photons available and has no self shafowing loss. The disadvantage is mainly dirt accumulation which will not be washed off by rain. For that reason you would want some tilt. But that causes self shadowing when the sun is low so you now have to separate the rows to reoptimize.
The second disadvantage os packing in horizontsl panels is that the cost of panels increases by the secant of your latitude. That disafvantage gets less as panels get cheaper.
I have written software to design optimum arrays versus latitude. You can optimize for energy per year from a given land area or energy for a given cost or a conbunation by plugging in cost of land. I never found tracking to give any advantage at panel costs under $1 per watt.