Tracker Suppliers Develop Site-Specific Stow Strategies

Stow strategies are becoming increasingly differentiated across tracker suppliers. They now depend not only on site conditions and meteorological inputs, but also on tracker architecture and the specific type of extreme weather event. Antaisolar, for example, outlined 4 different stow strategies based on tracker structure, location, and site weather conditions. In the event of higher wind loads, the tracker stows parallel to the prevailing wind direction. The tracker adapts to 0° (module lay float) during floods. In case of snow, the tracker stows at its maximum tilt angle to prevent snow from piling up on the modules. The same stowing strategy is also used to navigate through hail events (see Safety And Stowing Strategies For Trackers).

“The stowing strategy of the tracker also depends on the tracker configuration,” says Chintan Patel, CTO of Sunchaser, “especially if the product is based on single or multi-drive.” Sunchaser’s flagship multi-drive tracker uses a 0° (horizontal) stow position under high-wind conditions. The horizontal stow is facilitated by the uniformly distributed torsional stiffness along the full table length in a multi-drive configuration, according to Patel. In contrast, single-drive systems cannot easily accommodate 0° stow, as stiffness is concentrated near the central drive, and the table ends rely on dampers. In such systems, horizontal positioning may lead to flutter, emphasizes Patel. Therefore, single-drive trackers typically employ a tilted, nose-down stow aligned with the wind direction. If wind direction changes, the tilt rotates accordingly, though the behavior becomes less predictable when the wind comes from the north or south. Patel added that multi-drive systems provide uniform stiffness, enabling stable 0° stow and allowing wind behavior to be evaluated using natural frequency-based calculations rather than extensive wind-tunnel validation when modifying table lengths. As for the overall reliability of trackers, Sunchaser performs accelerated life-cycle testing on full-size trackers in environmental chambers (see Smarter Control Systems Drive Solar Tracker Performance).

Axial configured distinct stow angles according to product configurations. The company’s 2P systems stow at 5°, enabling faster transition into a safe position and reducing exposure during sudden gusts. Its 2P trackers feature a multi-point blocking system in which 2 piles share a single, synchronized slew drive connected via a mechanical transmission line. This configuration creates blocking points every 6 m, improving torsional stiffness and load distribution, according to Rodolfo Sejas, Business Development Specialist at Axial Structural Solutions. In contrast, the 1P trackers are designed to stow at 45°. Sejas substantiates thestrategy, referring to the performance of a 280 MW project in Sicily that was exposed to wind speeds above 200 km/h with no major structural failures.

Soltec defines its stow strategies based on CFD simulations and aeroelastic wind-tunnel testing with institutes such as RWDI and CPP, according to Sejas. For its 2P platforms, the company identifies 45° as the optimal compromise between tube bending and torsional stiffness. For 1P trackers, torsional loads are higher, so Soltec applies differentiated stow angles: 55° for exterior rows and 30° for interior or edge rows. In snowy conditions, steep tilt angles are used to reduce snow accumulation. In flood-prone areas, tracker movement is automatically constrained to prevent modules from dipping into standing water.

During hail events, the system selects stow positions that minimize impact forces based on the expected trajectory. According to Soltec’s hail whitepaper, the system combines data from hail-impact sensors with short-term weather forecasts to trigger early alerts, which enables the plant to stow preemptively rather than relying on manual activation or delayed sensor response. Once active, the algorithm positions trackers between roughly 55° and 70°, an orientation aligned with typical hail-impact angles for 25-50 mm hailstones. The hail logic also adjusts stow angles based on wind direction and uses fast-response motors (up to 20°/min) to minimize exposure during rapidly evolving storms.

Solar Steel’s TracSmarT+ control platform also incorporates weather-driven protection modes, including hail and snow. It is facilitated with an integrated climate-prediction system that provides project-specific wind alerts and supports earlier stow decisions. The Company offers additional tools, including directional stow, predictive maintenance, and customizable operating positions (see Advanced Tracker Controllers And Algorithms In Solar Trackers).

PVH also underscores its weather-response capabilities, including wind-adapted stow settings, ultrasonic wind alarms, and a hail-stow option of up to 75°.

The ZIMTrack system from Zimmermann uses a flat stow position facing the wind to reduce structural loads on modules and tracker components under high-wind conditions. According to the company, specific stow strategies are also defined for hail, snow, and flooding events.

Overall, the trackers are becoming increasingly resilient against extreme weather conditions. On the hardware side, the companies are carefully designing the products, taking the inputs from physical and simulated wind tunnel tests. As to navigation through extreme weather conditions in real time during field operations, the approaches reflect a broader industry march towards a granular, site-specific, weather-condition-driven stowing strategy, rather than standard stow positions.

The text is an edited excerpt from TaiyangNews’ latest Market Survey on Solar Trackers 2026, which can be downloaded for free here.