Duel Axis Solar Tracker

Image source: Aurora Solar Energy

Ground and roof-mounted solar trackers are rising in popularity, but like many technologies, there are both benefits and potential drawbacks to making the switch to axis trackers. These solar solutions are currently the most advanced technology for mounting panels, and a growing number of commercial enterprises and homeowners are taking advantage of it.

Stationary arrays are limited by the amount of sunlight they can absorb. Their static position means the angle of the sun also affects their productivity. But axis trackers automatically follow the sun as it moves through the sky. This function maximizes the electrical output. However, does that increase make an axis tracker a worthwhile investment?

What is a sun tracking solar panel?

The word "tracker" describes both the device and its ability to make a photovoltaic (PV) module follow the sun. There is literally no other technology that can increase the output of a solar array like a tracker. By maintaining constant, direct exposure to the sun, a tracker can improve a system's output by up to 40 percent over a traditional fixed-tilt system. The type of tracker and the region in which it's installed can further improve or decrease performance.

What types of axis trackers are there?

The two types of axis trackers, single and dual, produce different amounts of energy. For example, a single-axis tracker on a solar panel system can increase electrical productivity by 25 to 35 percent. A dual-axis tracker increases that boost by as high as another 10 percent. If you live in an area where the sun's position in the sky changes drastically between summer and winter, a dual-axis tracker can collect more than enough power for your entire home.

However, in many areas, the sun doesn't shift position enough to make a serious change in energy production. If considering making the switch to an axis tracker system, make it a point to do some research and speak to more than one solar company. In many states, utility companies offer special rate plans to consumers who use solar power. These Time of Use plans are based on energy collected during peak times. The utility purchases the power at higher rates. In this case, using an axis tracker will generate a greater amount of electricity during those peak times, earning you more.

How does a solar tracker work?

A single-axis system tracks the sun on its normal east to west trajectory, while dual-axis trackers have the extra ability to also change the tilt of the panels to capture even more of the sun's rays. Both types can be either active or passive. Active trackers depend on built-in software or electronic light sensors to follow the sun. Actuator drivers or motors physically move the panels. On the other hand, the earth's gravity and the sun's heat move the panels on passive tracker systems. The panels change direction when the weight of heated compressed liquid gas flows to either side of the array.

Are solar trackers the same as ground-mounted solar panels?

Most stationary ground-mounted solar modules are set into fixed-tilt supports. They're positioned to catch the maximum amount of sun at peak times of the day. The frameworks are anchored to the ground, usually on concrete foundations. Ground-mounted solar tracker systems are mounted in much the same way but may require extra prep work to accommodate specialized equipment.

How do you determine the ideal placement of solar panels?

Axis trackers can be installed as ground or roof systems, but they generate more electricity using about the same amount of space as fixed systems. This not only makes them a viable roof system, it makes it somewhat easier to determine which type of tracker will best fit each location.

How much extra does a single axis solar tracker cost?

Single Axis Solar Tracker

Image Source: Ministry of Solar

The price of a single axis tracker system can vary widely according to a huge range of variables, from size to type to the number of panels to location. For a standard 4kW system, the typical price for a fixed, ground-mounted array is about $14,000. A single-axis tracker system serving the same size home costs about $22,000. This is a premium of 57% over the cost of a stationary array for a solution that will only increase production by around 25-30% at best.

So at first instance it would seem that it is cheaper to simply install more solar than to incur the extra cost of an axis tracker. However, there may be instances in which you have limited space and so an axis tracker might be the only solution to get more electricity generation from that space.

How much extra does a dual axis solar tracker cost?

A dual-axis tracking system is a more complex structure which includes a variety of sensors, circuits motors, and drives, power management features, and software and hardware for remote controlling. One of these systems should start at about $28,000. The same argument applies for a dual axis tracker in that it is a 100% price premium for a 40% increase in electricity production and so it is cheaper to simply install more solar panels for most people that have the room to do so.

What are the pros and cons of solar trackers?

PROS:
  • Axis trackers offer a greater electricity generation and gross income in the long run because of their ability to follow the sun and collect more energy.
  • The variety of trackers now available makes it possible to find the right unit for your small or uniquely shaped or situated property.
  • Solar trackers offer homeowners the opportunity to earn more money if their local utility company offers a TOU purchase plan with peak periods extending into the afternoon in summer, when days are long..
CONS:
  • They are proportionately more expensive than the extra power the produce
  • These systems include several different and specialized moving parts, which call for more and regular maintenance than fixed arrays. Look for a contractor that offers a preventative maintenance plan.
  • Installing such a complex solar system may involve additional site preparation, including digging additional wiring trenches and extra site grading.
  • Location can influence the efficiency and lifetime of tracker systems. Trackers installed close to salt water may require implementing additional protective measures.

Will the additional energy generation from a solar axis tracker justify the additional cost in the long run?

We've already touched on a few of the variables to consider when looking at axis trackers but as a general rule, based on known published pricing, axis trackers need to become around 50% cheaper to be economic. It is very difficult to get any visibility as to pricing of serious solar axis tracking mounting solutions because such solutions are generally only sold to large industrial and utility-scale projects.

Ask for quotes for active and passive axis trackers in single and dual options. It may be that there are already cheaper axis trackers out there that do not advertise their price widely online. Compare every quote with the type of equipment being offered, up-front and maintenance costs, projected returns in energy output and savings. If you're interested in a renewable energy source to help defray the increasing cost of electricity, an axis tracker may offer enough long-term benefits to justify initial and ongoing operating expenses.