solar trackers overview

Solar trackers: everything you need to know

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There are many unique ways to design and install a solar energy system for your property. If you are considering a ground-mounted solar panel installation, you might be considering a solar tracking system so that your panels follow the sun across the sky. This article will examine what installing a solar tracker means and if a tracking system is right for your solar project.

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What to know about solar trackers

  • Solar trackers help maximize solar production by following the sun throughout the day
  • Solar trackers are usually used in commercial installations or other large ground-mounted arrays
  • Join the EnergySage Marketplace today to freely compare quotes for customized solar quotes

What are solar trackers? Single-axis vs. dual-axis solar trackers

A solar tracking system maximizes your solar system’s electricity production by moving your panels to follow the sun throughout the day, which optimizes the angle at which your panels receive solar radiation. Solar trackers are typically used for ground-mounted solar panels and large, free-standing solar installations like solar trees. They are typically not used in most residential solar projects, but have a place in the utility-scale and commercial/industrial solar market.

When solar panels are exposed to sunlight, the angle at which the sun’s rays meet the surface of the solar panel (known as the “angle of incidence”) determines how well the panel can convert the incoming light into electricity. The narrower the angle of incidence, the more energy a photovoltaic panel can produce. Solar trackers help to minimize this angle by working to orient panels so that light strikes them perpendicular to their surface.

There are two types of solar tracking systems: single-axis and dual-axis.

  • A single-axis tracker moves your panels on one axis of movement, usually aligned with north and south. These setups allow your panels to arc from east to west and track the sun as it rises and sets.
  • A dual-axis tracker allows your panels to move on two axes, aligned both north-south and an east-west. This type of system is designed to maximize your solar energy collection throughout the year. It can track seasonal variations in the height of the sun in addition to normal daily motion.

Typically, dual-axis trackers (made by companies like AllEarth Renewables) are a much less popular option for solar installations, even among large, utility-scale projects. A situation where dual-axis trackers may be appropriate would be on some commercial properties – due to limited commercial rooftop space for solar panels to be installed, dual-axis trackers that can produce up to 45% more energy than typical static panels can help businesses produce enough power to fuel their operations in a small space. Utility-scale installations usually don’t need dual-axis setups, because they are located on large plots of land without the tight space constraints of a commercial roof space.

Active vs. passive solar trackers

Aside from the difference between single-axis and dual-axis trackers, there are also active and passive solar trackers. Most tracking systems out there are active systems – this means that the tracking system is provided with energy to run a motor or other mechanical device that tilts the attached solar panels the right way. On the other hand, passive solar trackers also track the sun, but without any added energy source. They move by using the heat from the sun to warm a gas. When that gas expands, it causes a mechanical movement of the solar panels. When the sun moves and the gas cools, it compresses again and the panels move back. The actual science behind passive solar trackers is more complicated than this description, but we’ll stay simple for now. The key takeaway: active solar trackers use a motor to move, and passive solar trackers use the sun to move.

In general, active solar trackers are more well-suited for large and complex installations, while passive trackers can be used for simple PV systems and not much else, given their lower accuracy.

Benefits and drawbacks of solar trackers

The biggest benefit of a solar tracking system is that it offers a boost in electricity production. Generally, a solar panel system with a single-axis solar tracker installed sees a performance gain of 25 to 35 percent. A dual-axis tracker bumps performance up by another five to 10 percent.

If you live in a high latitude where the sun’s position in the sky varies dramatically between summer and winter months, a dual-axis tracking system may be a good way to maximize your solar production and collect enough power for your home or property.

However, there are some disadvantages of having a solar tracking system. They tend to have higher installation and maintenance costs. A solar tracker will cost more money up front than a fixed solar panel system because it is a more complex technology and has moving parts.  This also leads to the second area of increased cost for solar tracking systems: maintenance. With a more complex system comes more maintenance, which can add up in cost over time.

Another disadvantage of a solar tracker is that they are typically too heavy to be used in rooftop solar projects. If you want a solar panel system that has tracking features, be prepared to install a ground-mounted array.

Is a solar tracking system right for you?

A rooftop installation offers lower costs and doesn’t require dedicated yard space, making it the preferable option for most solar-interested homeowners. As a result, most home solar systems don’t include solar trackers. If you have a south-facing roof, your solar panels will already be oriented to capture maximum sunlight, which reduces the need for a tracking system.

Solar trackers offer the greatest value proposition in high latitude locations due to the yearly movements of the sun. For this reason, solar customers in Alaska and some northern parts of the contiguous U.S. may want to look into including trackers with their system. However, for the majority of US residents, the sun’s movement will not impact your panel production to the point where a tracking system offers significant financial benefits. Most customers are better off installing a rooftop array on a south-facing surface, or a fixed ground mounted system facing south.

Solar tracking systems are also often used in large commercial projects, typically over 1 megawatt (MW). For commercial-scale solar arrays, the long-term benefit of increased production over time is enough to make the initial cost and maintenance fees worth it. Additionally, commercial-scale solar projects are typically ground mounted, making solar trackers a possibility.

Find the right solar setup for your property

Whether you want a ground-mounted solar array with solar trackers or a rooftop system, it is always important to compare your options before moving forward. On the EnergySage Solar Marketplace, you can solicit quotes for both ground-mounted and rooftop solar projects from qualified, pre-vetted installers in your area. If you are interested in a tracking system, simply leave a note on your profile that you would like quotes including solar trackers.

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About Jacob Marsh

Jacob is a researcher and content writer at EnergySage, where he focuses primarily on current issues–and new technology!–in the solar industry. With a background in environmental and geological science, Jacob brings an analytical perspective and passion for conservation to help solar shoppers make the right energy choices for their wallet and the environment. Outside of EnergySage, you can find him playing Ultimate Frisbee or learning a new, obscure board game.

7 thoughts on “Solar trackers: everything you need to know

  1. Samantha Davis

    I am writing you this email to ask a question. I am a student from Brentwood College School on Vancouver Island. We are doing a school project on ‘How might I change Salt Spring Island’s access to electricity to make it more sustainable?’ What I have decided to do as my project is I chose salt spring island and for my project, I decided to add a hybrid system between solar power and wind power alternating through the seasons and the work together with the already exciting hydropower. I was wondering on average how many Rotating solar panels(Solar Trackers) would you need to run a town of 3000 people and how much would it cost? Including installation fees approximately.

    Samantha Davis

  2. Keith Winston

    I believe two points were missed.
    First: a tracker, by efficiently increasing it’s solar exposure by more-nearly remaining normal to the suns’ rays, proportionally increases the shade it throws: which means that arrays have to be spaced further apart to avoid inter-row/inter-array shading.
    As module pricing comes down, the value of increasing performance per module diminishes, and it becomes more reasonable to think of energy per square meter of installation space. Just add more modules, with a reasonable South or E-W dual-tilt system. No moving parts!
    Also: having moving parts in harsh climates like Alaska is counter-indicated. Instead, a manually-adjusted seasonally-optimized system might make more sense. Tweak the tilt 2-3 times a year, which also gives you your steepest tilt in highest-snowfall periods.

  3. Grant

    Now that net-metering is becoming a thing of the past, this article is deeply misleading. A simple dollars-per-watt-hour comparison is insufficient, as you also need to consider when watt-hours are produced and when watt-hours are consumed. South-facing panels don’t receive enough sunlight to generate ANY power when most households are at peak consumption, so simply adding more south-facing panels doesn’t fix the problem. Tracking panels, on the other hand, keep producing through most of the peak usage hours, something you could only do by using double the number of panels in a combination of east- and west-facing arrays.

    Now, I suspect that neither of those options is economical in comparison to simply adding battery storage to a south-facing system, but the fact remains that the economics of single-axis trackers aren’t nearly as bad as this article suggests.

  4. Virgil Banowetz

    Please address a tracker with a single axis aligned with the earth polar axis. It could be simpler and have almost the same efficiency as a dual axis tracker that would not adapt to the seasons. If it could be counterbalanced, it would take very little energy to rotate it.

    1. Larry M.

      Agree with Virgil – if single axis align with axis of rotation of the earth, efficiency will be close to dual axis tracker. Every single rotation unit better place on large flat bearing, it will help to protect flat solar panels from wind. Single moving gear could move 3, 4 maybe 5 or 6 units by circle chain.

  5. Billy Zeier

    Hey Jacob,

    Thanks so much for he article about single and duel axis trackers.

    Could you tell us where you get your data from in Regards to how much better trackers (single and duel) perform over static solar systems?


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