What Is a Solar Panel Tracker?

How solar panels work

Solar panel trackers use sensors, motors and control systems to automatically adjust panel orientation throughout the day. This section explains how these components work together to maintain optimal sun alignment and the key differences between active and passive tracking systems.

Key components

Solar trackers rely on four primary components working in harmony.

• Light sensors (photosensors): Detect the sun's position by measuring light intensity from different angles. When sensors on opposite sides of the panel register unequal light levels, this signals the need for adjustment.
• Controllers: Serve as the system's brain, processing sensor data and calculating the precise movements needed. Modern controllers use algorithms that factor in time of day, date and geographic location to predict optimal positioning.
• Motors: Provide the mechanical power to rotate the tracking structure. Single-axis systems typically use one motor, while dual-axis trackers employ two for both horizontal and vertical movement.
• Actuators: Convert the motor's rotational force into linear motion, physically adjusting the panel's angle. These components work continuously throughout daylight hours, making micro-adjustments every few minutes to maintain perpendicular alignment with incoming sunlight.

Active vs. passive tracker operation

Solar trackers operate using either active systems with motorized controls or passive systems that rely on thermal physics to create movement.

Active trackers

Active trackers use motors and electronic controls powered by electricity to move panels. They employ sensors or GPS-based algorithms to follow the sun precisely during the day. Commercial solar farms typically use active trackers because they offer superior accuracy and can be programmed for optimal performance. For example, NEXTracker's systems adjust panels every few minutes based on real-time calculations.

Passive trackers

Passive trackers rely on thermal expansion of compressed gas or liquid to create movement without motors or electronics. As the sun heats one side of a hydraulic system, the fluid expands and shifts weight, causing the panel to tilt naturally. Zomeworks manufactures passive trackers that use this low-tech approach, making them ideal for off-grid installations where electrical power for motors isn't available or practical.

Types of solar panel trackers

Solar panels can be mounted on solar panel trackers, which position the solar panels throughout the day to get the most sunlight possible. The more sunlight a panel gets, the more energy it can create. There are several different types of solar panel trackers.

Active and passive solar panel trackers

Solar panel tracking systems that move themselves are divided into passive and active categories. Active systems use electricity to position the panels using hydraulics, sensors and computers to determine the best position for the panel throughout the day.

Solar panel trackers help maximize a panel’s output but can be expensive.

These systems are sub-categorized into two tracking types: Some systems use algorithms to determine the best position for the panel, while others use light sensors.

Instead of being electrified, passive systems use a gas that is heated by the sun. As the gas is heated, it moves, tilting the panel with gravity. Passive systems have fewer moving parts and no electronics, requiring less maintenance.

» DISCOVER: What are ground-mounted solar panels?

Manual solar panel trackers

Manual solar panel trackers are human-powered — you’ll need to go outside and reposition the panels throughout the day to collect the most sun. While this sounds like a pain, these trackers are less expensive and don’t require as many repairs as active or passive trackers.

Dual- and single-axis solar panel trackers

Single-axis trackers follow the sun as it rises in the east and sets in the west. Single-axis mounts can provide 15% to 25% more output than nonmoving mounts.

Dual-axis trackers follow the sun east to west throughout the day, like single-axis trackers. They can also follow it north to south as the seasons change, though. This extra feature makes them up to 2.4% more efficient.

Where are solar panel trackers used?

Solar trackers are commonly used in utility-scale solar farms, occasionally used in commercial settings, and rarely found in residential systems. Whether they’re needed depends on project scale, available space and whether increased energy production is worth the higher upfront costs and maintenance.

Utility-scale solar farms

More than half of utility-scale solar installations in the U.S. use tracking technology. Large solar farms favor trackers because increased energy production offsets higher equipment costs when spread across thousands of panels. The systems maximize energy capture throughout the day, helping achieve higher returns on investment.

Commercial and industrial facilities

Commercial facilities adopt trackers when space is limited or energy demands are high. Trackers allow businesses to maximize energy output in constrained roof or ground space, making them attractive for optimizing performance. The higher upfront costs are more manageable for businesses with larger budgets and longer return-on-investment (ROI) timelines.

Residential solar systems

Trackers are rarely used residentially because they typically aren't worth the investment. A standard 4-kilowatt ground-mounted system costs around $13,000, but adding single-axis tracking increases costs to $20,000. Simply adding more panels would be less expensive. Trackers also require ground mounting, dedicated yard space and ongoing maintenance.

Fixed vs. single-axis vs. dual-axis solar systems

Choosing between fixed, single-axis and dual-axis solar systems involves balancing energy output gains against upfront costs and maintenance requirements. Fixed panels serve as the baseline, single-axis trackers boost efficiency by about 26%, while dual-axis systems offer the highest gains but come with significantly higher complexity and costs.

Efficiency and output

Single-axis trackers achieve energy gains of 20% to 35% compared with fixed systems, primarily by following the sun's east-west movement throughout the day. Dual-axis systems deliver 35% to 45% more energy than fixed panels by tracking both horizontal and vertical sun movement. Single-axis tracking is about 20% more efficient than fixed-tilt systems, while the additional 5% to 10% gain from dual-axis often doesn't justify the added expense for large installations.

Cost and maintenance

Fixed systems offer better ROI for most commercial rooftop applications, providing reliability with minimal maintenance. Single-axis trackers are ideal for utility-scale solar farms where land is available, balancing performance and cost-effectiveness. Dual-axis systems work best for smaller residential or commercial installations with limited space where maximum output is essential.

Can I use solar panel trackers with my home’s solar panels?

There are solar panel trackers made for home use, some of which you can purchase online. Solar energy system companies also sell trackers to their customers.

Trackers are expensive, though, and potentially not worth the investment. Most trackers available cost anywhere from $500 to $10,000 each. In most cases, homeowners would be better off just buying extra panels to boost solar output than purchasing trackers for panels.

“Currently, the most cost-effective solution is installing solar panels on exposed rooftops that get sun exposure either throughout the day or during a significant part of the day,” said Shaun Sharabi, the co-founder of Better Earth, a solar energy company.

» LEARN MORE: How much do solar panels cost?