Solar Trackers Explained

he use of solar trackers is a common practice in the photovoltaic industry, with the invention of the first solar tracking system dating back to 1962. Though the first solar tracker did not yield significant energy gains, solar technology has greatly progressed, making modern sun tracking systems more efficient. This article will take you through the basics of modern solar tracking systems and help you decide if they are worth exploring further.

Solar basics: How does solar power work?

Before jumping straight to the topic of trackers, let's first take a look at how solar panels use the sun to produce electricity. Simply put, PV panels work by absorbing sunlight and converting it into solar power due to the photovoltaic effect. The more sunshine they get, the more power they produce. So, to achieve a high solar production efficiency, good sunlight exposure is of paramount importance.

What is a solar tracker, and how does it improve solar performance?

A solar tracker is a mechanical system that tracks the position of the sun during the day. Coupled with solar panels, a solar tracking system optimizes the angle at which the light strikes the surface of your photovoltaic modules, making your panels follow the sun, just like a sunflower in your garden.

The angle between the incoming sunlight and your solar panel determines how well the solar system will perform. The narrower this angle is, the more power your system will generate. Solar trackers help to minimize this angle by orienting panels so that they are adjusted perpendicular to the sun.

Most often, solar trackers are used for ground-mounted solar systems, but some new models are designed for rooftop photovoltaic installations. Solar trackers are usually connected to the racking of the solar panels, which is the foundation of your solar system that holds your solar setup in place.

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Three basic types of solar trackers

There are two main ways to classify solar tracking systems. One approach is to divide them into active, passive, or manual. Let’s discover the difference between these three types of solar trackers.

Active solar trackers

Active solar trackers are the most common type of trackers. Such tracking systems use energy to run motors or hydraulic cylinders that move panels so that they follow the sun. Despite being highly precise and effective, active trackers are prone to breakdowns due to their moving parts. Thus, active trackers often require more maintenance, resulting in a higher cost.

Passive solar trackers

Passive solar trackers also make your PV panel system follow the sun without any added energy source. These trackers contain a liquid that evaporates under sunlight exposure. When the liquid evaporates, it causes a mechanical movement of photovoltaic modules toward the direction of the solar rays. Passive trackers are less expensive but also less efficient and won’t work when it’s cold.

Manual solar trackers

A manual solar tracker requires someone to manually adjust the panels throughout the day so that they follow the sun. On the one hand, such a tracker can be an appealing choice for those on a budget, as it is significantly cheaper than all other trackers. However, the main inconvenience with these trackers is that you need someone to constantly track and control the sun and adjust the position of the PV panels.

Single-axis vs. dual-axis solar tracking technology

Solar trackers can come in either single-axis or dual-axis varieties. Let’s have a quick glance at these two types of solar tracking systems.

Single-axis type

Single-axis solar trackers follow the sun as it moves from east to west, rotating on a single point either on a horizontal or a vertical axis. These trackers are usually used for utility-scale projects on flat land in a warm area. A single-axis tracker can boost the efficiency of a photovoltaic system between 25% to 35%. Recently, such trackers have become a standard in utility-scale applications.

Dual-axis type

Dual-axis solar trackers allow your photovoltaic panels to follow the sun directly, rotating on both the horizontal and vertical axes. Solar systems equipped with these trackers can produce up to 45% more power than fixed-tilt systems by tracking seasonal variations in the height of the sun along with following its daily movement. Dual-axis trackers are more expensive, hence, more used for residential projects with tight space and higher requirements for the efficiency of the PV system.

Extra price for extra solar efficiency

Those willing to increase the performance of their solar panel system should always be ready to pay extra – this is also the case with solar trackers, which can hugely boost solar energy production.

In most cases, photovoltaic panels with a tracking system cost between 40 to 100 percent more than a solar system without it. The price you’ll pay for it depends on the type of solar tracker.

The price of a solar tracking system can vary from $500 to over $1,000 per panel. If you're considering a 4-kilowatt, ground-mounted solar kit. For such a photovoltaic system, the price will likely be around $13,000. If you decide to add single-axis equipment, it will increase the cost of your photovoltaic panel system up to around $20,000. A dual-axis solar tracker will require even more expenses, with a total price of a solar panel system reaching about $26,000.

The sun's power output, measured in watts per square meter, is crucial for calculating solar energy potential and designing efficient photovoltaic systems.

Best solar trackers on the solar PV market

The U.S.-based company Nextracker is the leading provider of solar tracker solutions used in ground-mounted solar panel systems for utility-scale applications. Their TrueCapture and NX Navigator smart optimization software tools are highly valued in the solar tracking market.

Array Technologies, also headquartered in the United States, has over 28 years of experience producing high-quality and sophisticated solar tracking solutions for residential, commercial, and utility applications, with DuraTrack being one of its best solar tracking products.  After acquiring the Spanish STI Norland, Array Technologies has become the largest solar tracker company in the world.

Pros and cons of enhancing a solar system with an ST solar solution

Solar tracking equipment can greatly enhance the performance of your photovoltaic panels, but it is crucial to consider certain potential downsides before purchasing one.

Benefits of solar trackers

• Photovoltaic systems with solar trackers can generate more electric power than their stationary counterparts because they can be adjusted to the position of the sun.
• More energy generation means you need fewer solar panels to satisfy your electricity needs, so with the use of solar trackers, you don’t need as much space for your solar installation.
• In certain areas, some utilities can offer a Time of Use (TOU) rate plan for the solar power your system produces. This means that the utility will buy your electricity generated during the peak time of the day at a higher rate. If this option is available for you, you will be interested in producing a greater amount of electric power during these peak times, and in this case, a solar tracker can be really helpful.

Drawbacks of solar trackers

• If you opt for a photovoltaic system with a solar tracker, be prepared for some extra expenses. Solar tracking equipment can easily double the cost of your PV panel project.
• Solar trackers consist of moving parts normally associated with many possible points of failure, and, respectfully, trackers incur higher maintenance costs for the added complexity.
• Choosing to install solar trackers is likely to imply more site planning and preparation, including digging additional wiring trenches and extra site grading. Also, trackers are often too large and heavy for rooftop solar panels, so keep in mind that if you decide to set up a tracking system, there is a high chance you’ll have to install a ground-mounted solar kit.

Bottom line: Is buying a solar tracker worth it for your solar panel setup?

Solar trackers are generally more useful in large-scale utility or commercial PV installations. For residential systems, consider other options for improving panel efficiency before investing in trackers, as they won’t come cheap. As always, it is essential to consider the disadvantages to determine whether they will not overshadow the potential benefits.