What Is Solar Tracker? Definition & Guide

Key Takeaways

Single-axis trackers increase energy yield by 15–25% and dual-axis by 25–35% compared to fixed-tilt systems
Single-axis trackers dominate utility-scale solar, used in over 70% of new ground-mount installations in the U.S.
The added cost of tracking is offset by higher energy production — improving LCOE by 5–15% in high-DNI locations
Trackers require more land area due to wider row spacing to prevent inter-row shading
Backtracking algorithms prevent row-to-row shading during low sun angles
Accurate solar design software is needed to model tracker gains with site-specific weather and terrain data

What Is a Solar Tracker?

A solar tracker is a motorized mounting structure that orients solar panels to follow the sun’s path across the sky throughout the day. By keeping the panel surface closer to perpendicular to incoming sunlight, trackers reduce the angle of incidence and increase the amount of solar radiation captured compared to a fixed-tilt system.

Fixed-tilt systems are set at a static angle (typically near the site’s latitude) and can only be optimal at one point during the day. Trackers continuously adjust panel orientation — either on one axis (east-to-west rotation) or two axes (east-to-west plus seasonal tilt) — to maximize energy capture from morning to evening.

Single-axis trackers have become the default mounting choice for utility-scale solar in North America and Australia. The 15–25% production boost they deliver more than justifies the 8–12% cost premium over fixed-tilt racking.

How Solar Trackers Work

Tracker operation involves mechanical movement controlled by software algorithms:

Position Calculation

The tracker controller calculates the sun’s position using astronomical algorithms based on latitude, longitude, date, and time. Some systems supplement this with GPS and light sensors for fine-tuning.

Motor Actuation

Electric motors (typically slew drives or linear actuators) rotate the tracker structure to align panels with the calculated optimal angle. Movement is slow and continuous, consuming minimal energy.

Backtracking

During early morning and late afternoon, adjacent tracker rows would shade each other if fully oriented toward the sun. Backtracking algorithms intentionally under-rotate panels to eliminate row-to-row shading, maximizing total array output.

Weather Response

Advanced trackers incorporate weather data and sensors. During high winds (typically above 50 mph), trackers move to a stow position — usually flat or at a defensive angle — to reduce structural loads and prevent damage.

Night/Cloud Positioning

At sunset, trackers return to the morning start position to be ready for the next day. During overcast conditions, some systems flatten panels to capture maximum diffuse radiation rather than tracking direct sun.

Tracker Gain

Tracker Gain (%) = ((Tracked Energy − Fixed Energy) ÷ Fixed Energy) × 100

Types of Solar Trackers

Industry Standard

Single-Axis Horizontal (SAT)

Rotates east-to-west around a horizontal north-south axis. The dominant tracker type for utility-scale solar, offering 15–25% energy gain at 8–12% cost premium. Rows of panels tilt together on a shared torque tube driven by a single motor per row or linked rows.

Maximum Yield

Dual-Axis Tracker (DAT)

Rotates on two axes — azimuth (compass direction) and elevation (tilt angle). Captures 25–35% more energy than fixed-tilt. Higher cost and complexity limit use to concentrated PV (CPV) and high-value applications where maximum energy per panel matters.

Tilted

Single-Axis Tilted (TSAT)

Rotates east-to-west around a tilted axis. Provides slightly higher energy capture than horizontal SAT at higher latitudes where the optimal fixed tilt is steep. Less common due to higher wind loading and structural cost.

Niche

Vertical-Axis Tracker

Rotates panels around a vertical axis (like a turntable) while maintaining a fixed tilt angle. Used in some rooftop and carport applications where horizontal rotation isn’t feasible. Limited market share.

Designer’s Note

Single-axis horizontal trackers deliver 80–90% of the energy gain of dual-axis systems at roughly half the additional cost. For almost all utility-scale and commercial ground-mount projects, single-axis is the right choice. Dual-axis only makes sense for CPV or extremely space-constrained high-value sites.

Key Metrics & Calculations

Metric	Unit	Typical Range
Tracker Gain (SAT)	%	15–25% over fixed-tilt
Tracker Gain (DAT)	%	25–35% over fixed-tilt
Rotation Range (SAT)	degrees	±50° to ±60°
Motor Power Consumption	kWh/year per MW	500–1,500 kWh
Wind Stow Speed	mph	40–55 mph
Ground Coverage Ratio	—	0.25–0.35 (vs. 0.40–0.50 for fixed)
LCOE Improvement	%	5–15% in high-DNI locations

LCOE with Tracker

LCOE = (System Cost + Tracker Premium + O&M) ÷ (Fixed Energy × (1 + Tracker Gain%))

Practical Guidance

Tracker selection and design affects project economics, site layout, and long-term O&M requirements:

Model backtracking accurately. Without backtracking, inter-row shading losses during morning and evening hours can erase 3–5% of theoretical tracker gains. Ensure your simulation software models backtracking behavior correctly.
Account for terrain. On uneven terrain, tracker rows at different elevations create complex shading patterns. Use shadow analysis tools that handle terrain-aware tracker modeling.
Factor in GCR tradeoffs. Trackers require lower ground coverage ratios (wider row spacing) than fixed-tilt to prevent shading. This means more land area per MW but higher energy per MW installed.
Use SurgePV’s design tools to compare tracker vs. fixed-tilt layouts side by side, with accurate energy yield and financial projections for each option.

Verify soil conditions. Trackers transmit higher dynamic loads to foundations than fixed racking. Geotechnical surveys are mandatory — driven piles in soft or expansive soils may require different designs than in rocky terrain.
Commission tracking algorithms. After mechanical installation, verify that each tracker row moves correctly through its full range of motion and that the backtracking algorithm activates at the right solar angles.
Test wind stow functionality. Simulate a high-wind event to confirm that all rows stow within the specified time limit. A tracker that fails to stow in high winds can be destroyed.
Plan for O&M access. Trackers have moving parts that require periodic inspection — motors, slew drives, bearings, and controllers. Ensure maintenance vehicles can access every row.

Frame trackers as an investment, not a cost. The 8–12% price premium delivers 15–25% more energy. The math works out to a lower LCOE and faster payback in most utility-scale scenarios.
Show the production profile advantage. Trackers produce a broader, flatter daily production curve — delivering more energy during morning and evening peak-rate hours. In TOU markets, this increases revenue per kWh.
Address reliability concerns. Modern single-axis trackers have 99.5%+ uptime with 30-year design lives. Warranties typically cover motors and controllers for 10+ years.
Present bifacial + tracker synergy. Bifacial panels on trackers can capture an additional 5–10% from rear-side irradiance, stacking on top of the tracker gain for a combined boost of 20–35%.

Design Tracker and Fixed-Tilt Systems Side by Side

SurgePV lets you compare tracker vs. fixed-tilt layouts with accurate energy yield and financial modeling — all in one platform.

Start Free Trial

No credit card required

Real-World Examples

Utility-Scale: 200 MW Solar Farm in Texas

A 200 MW ground-mount project in West Texas compares single-axis tracker vs. fixed-tilt. The tracker option adds $0.04/W to the installed cost but increases annual energy yield from 380 GWh to 456 GWh — a 20% gain. At a PPA rate of $0.028/kWh, the additional revenue of $2.13M/year against $8M in added tracker cost produces a 3.8-year payback on the tracker premium alone.

Commercial Ground-Mount: 5 MW in Arizona

A 5 MW commercial installation in Phoenix uses single-axis trackers with bifacial panels. The combination delivers a 28% energy gain over fixed-tilt monofacial: 20% from tracking and 8% from bifacial rear-side gain. The higher production secures a more favorable PPA rate and shortens the project’s debt service coverage timeline by 2 years.

Distributed Generation: 500 kW Tracker in California

A 500 kW carport tracker installation for a shopping center in Southern California uses a custom single-axis design. The tracker produces 22% more energy than a fixed carport canopy, and the production profile better matches the building’s afternoon cooling load. The additional energy offsets an extra $18,000/year in electricity costs.

Tracker vs. Fixed-Tilt: Decision Framework

Factor	Favors Tracker	Favors Fixed-Tilt
Location DNI	High DNI (>5.5 kWh/m²/day)	Low DNI or high diffuse fraction
Land Cost	Low — land is abundant	High — maximize GCR
Project Scale	Utility-scale (>5 MW)	Small commercial or rooftop
Wind Exposure	Moderate (below 90 mph design)	Extreme wind zones
Terrain	Flat or gently sloping	Steep or highly irregular
O&M Budget	Available for periodic maintenance	Minimal O&M capability
PPA/Revenue	TOU or peak-weighted pricing	Flat rate pricing

Pro Tip

When evaluating trackers, don’t just compare annual kWh totals. Look at the hourly production profile. Trackers shift energy production toward morning and evening hours when electricity prices are often higher, creating value beyond raw kWh gain.

Frequently Asked Questions

How much more energy does a solar tracker produce?

Single-axis trackers typically produce 15–25% more energy than fixed-tilt systems, with gains toward the higher end in high-DNI locations like the U.S. Southwest, Middle East, and Australia. Dual-axis trackers add 25–35% over fixed-tilt. The exact gain depends on latitude, weather patterns, and how well the backtracking algorithm is optimized. Use solar design software with site-specific data to get accurate projections.

Are solar trackers worth the extra cost?

For utility-scale ground-mount installations in locations with good direct sunlight, single-axis trackers almost always improve project economics. The 8–12% cost premium is offset by 15–25% more energy production, resulting in a lower levelized cost of energy (LCOE). For smaller systems, the economics are tighter. Trackers are generally not used for rooftop installations due to wind loading and structural constraints.

What happens to solar trackers in high winds?

Modern trackers have wind stow systems that automatically rotate panels to a flat or defensive position when wind speeds exceed a threshold (typically 40–55 mph). This reduces the wind area and structural load to protect the system. Some advanced trackers use real-time wind sensors and dynamic stow algorithms that respond to gusts rather than sustained wind speed, minimizing unnecessary stow events that reduce production.

Can solar trackers be used with bifacial panels?

Yes, and the combination is increasingly standard. Bifacial panels on single-axis trackers capture additional energy from ground-reflected light on the rear side, adding 5–10% on top of the tracker gain. The combined effect delivers 20–35% more energy than monofacial panels on fixed-tilt racking. Most new utility-scale projects use this combination to maximize energy yield per hectare.