Dual-Axis Tracker

Key Takeaways

• Dual-axis tracker = rotation on both east-west and seasonal axes.
• +25-30% yield over fixed tilt.
• ~2× cost of single-axis tracker.
• Niche use; single-axis dominates utility scale.
• Best for high-latitude sites and research applications.

How the Two Axes Work

The primary axis on a dual-axis tracker mimics a single-axis tracker: it rotates the module table east to west over the course of the day, following the sun’s azimuth. The secondary axis is what sets it apart, it adjusts the tilt angle seasonally (and in some designs, continuously) to track the sun’s changing elevation as the seasons shift.

Together the two axes keep the module surface closer to perpendicular to incoming sunlight through more hours of the year than a single-axis tracker, which only corrects for azimuth and leaves elevation angle fixed or coarsely stepped.

That extra correction is where the incremental +25-30% yield gain over fixed tilt comes from, versus the +15-22% typical of single-axis systems.

The gain is largest at high latitudes and during winter months, when the sun’s elevation swings furthest from a design’s optimal fixed tilt angle, which is also why dual-axis trackers see more use in research installations and high-latitude sites than in equatorial utility-scale plants, where single-axis backtracking already captures most of the available gain at a fraction of the mechanical cost.

Why Dual-Axis Stays a Niche Choice

The math that keeps dual-axis trackers out of most utility-scale bids is straightforward: roughly double the mechanical cost (two drive systems, two sets of bearings, more complex foundations) for maybe 5-10 percentage points more yield than a single-axis tracker already delivers.

At utility scale, where land is available and IRR is driven by cost per watt, that trade rarely clears. Dual-axis systems also carry a larger wind-exposed profile than single-axis rows, which pushes up structural and foundation design requirements, a factor worth flagging early during civil design rather than after procurement.

Related Reading

Readers comparing tracking options before a design decision may find it useful to start with how automatic solar tracking systems work across single- and dual-axis configurations, which lays out the mechanical and control differences in more depth than a glossary entry allows. Because most trackers, dual-axis included, rely on backtracking logic to avoid row-to-row self-shading at low sun angles, the backtracking algorithm explainer is a natural next stop.

For teams modeling whether the extra yield actually justifies the cost on a specific site, the PVsyst tracker yield study methodology walks through the simulation steps used to quantify tracker gains before committing to hardware.

And since dual-axis structures carry higher wind loads than fixed racking, the pile foundation design guide for ground-mount systems and the related ASCE 7-22 wind load reading for rooftop and ground-mount solar are worth reviewing during the structural design phase.