What Is a Solar Tracker System? How It Works, Energy Gain, Cost and Site Requirements

BTR Enerji Engineering Team · Updated: 1 October 2026 · 5 min read

A solar tracker system is a PV mounting structure that rotates the modules to follow the sun during the day, increasing the irradiance that reaches the panels. In ground-mounted solar plants the most common type is the single-axis tracker (SAT): the modules rotate from east to west around a north-south axis.

How does a solar tracker work?

In a single-axis tracker the modules are mounted on a torque tube running north-south. Each row's tracker control unit (TCU) uses an astronomical sun-position algorithm to turn the row east in the morning, flat at noon and west in the evening. The typical rotation range is ±55–60°.

• Sun tracking: The modules face the sun as directly as possible all day, which gives a clear gain in the morning and evening (the shoulder hours).
• Backtracking: When the sun is low, rows are rotated back in a controlled way so they do not shade each other.
• Wind stow: When wind speed exceeds the manufacturer's threshold, the rows move to a safe stow position.
• Site communication: Row controllers (TCU) usually connect wirelessly to a network control unit (NCU), and wind and snow sensors monitor the site.

How much more energy does a solar tracker produce?

At the same installed capacity, a single-axis tracker typically produces 15–25% more annual energy than a fixed-tilt system. The main drivers of the gain are the share of direct irradiance, the latitude, bifacial modules with ground reflection (albedo), and near shading on the site. The exact figure is site-specific, so the decision should be based on a simulation that uses hourly weather data.

How much more does a tracker produce? (simulation data)

We simulated the same plant at 13 sites in the main tracker markets and 12 sites in Türkiye, once with single-axis trackers and once with fixed-tilt racking (PVGIS hourly weather, 710 W bifacial modules, identical loss assumptions). The median gain at the international sites was 22.2%; clear-sky regions such as the US Southwest reached 24–26%, while hazy or cloudy climates gained much less.

All 25 sites, the method and why the gain differs: Solar tracker energy gain by location.

Solar tracker vs fixed-tilt at a glance

For a detailed comparison see Solar tracker vs fixed-tilt.

Solar tracker cost

Because of the torque tube, slew drive and motor, controllers and piles, the initial investment is usually 8–12% higher than for fixed-tilt. On most sites the extra energy pays back this difference within a few years. For the cost items see Solar tracker cost and what drives it.

Terrain slope and earthworks

A tracker row is a straight beam, so the slope along the axis (north-south) should typically not exceed 10–15%. Small undulations are absorbed by adjusting the pile reveal; where the tolerance is exceeded, local grading is needed. Details: Solar tracker slope tolerance and earthworks.

Which projects suit a solar tracker?

• Megawatt-scale ground-mounted PV plants (utility-scale, merchant or PPA)
• Large, open, low-slope land
• Regions with high direct irradiance
• Projects with high morning or evening prices, or high consumption at those hours (self-consumption)

Frequently asked questions

How much more electricity does a solar tracker produce than a fixed system?

Depending on latitude, irradiance (especially direct irradiance), ground reflection and module type, single-axis trackers typically produce 15-25% more annual energy than a fixed-tilt system of the same capacity. The exact gain is site-specific and should be simulated with hourly weather data.

How much does a solar tracker system cost?

Because of the structure and control equipment, the initial investment of a tracker plant is usually 8-12% higher than a fixed-tilt plant. Thanks to the additional energy, this difference pays back within a few years on most sites.

What kind of land is suitable for solar trackers?

Trackers perform best on large, open land where the slope along the tracker axis (north-south) typically does not exceed 10-15%. On steeper land, local grading or shorter rows are used.

Are solar trackers expensive to maintain?

Because of moving parts (motor, gearbox, controller), O&M costs are somewhat higher than for fixed-tilt. With modern wireless, self-powered trackers the difference is small.

The ratios on this page are typical industry ranges and are not binding; exact values are determined by a site-specific analysis.