ARRAY Technologies highlighted its patented passive wind-stow technology, which has been incorporated into the DuraTrack and OmniTrack models
In addition to its safety function, the mechanically operated row-by-row passive stow mechanism earns additional power gain relative to the active stow method
According to the company’s in-house simulation tests, the passive stow strategy can lower the average energy losses to 0.05% compared to 2.8% for its active counterpart
During Intersolar Europe 2025, ARRAY Technologies, a US-based solar tracker making company, promoted its passively operated stowing functionality. According to the company’s website, this feature has been incorporated in the commercially available tracker models – DuraTrack and OmniTrack.
Extreme wind events can damage a tracker-based utility plant’s PV modules due to vibration and rotation. ARRAY published a white paper, which says that during such events, placing the modules at a safe stow position reduces the vibration, galloping, and rotation of the panels by making the system more stable and controlled. The company says a safe stow position can be achieved in 2 ways: active and passive. Inferring from the product specification table section of the TaiyangNews Solar Tracker Market Survey 2024 report, the safe stow angle might vary between 0° and 45° (download the TaiyangNews Solar Tracker Market Survey 2024 report here). However, the misalignment of the stowed trackers with the Sun’s real-time position for a certain duration results in potential energy losses. To meet both ends of providing safety and lowering potential generation losses, ARRAY Technologies chose the passive stow method.
It is based on a mechanical system that is activated by real-time wind force. Beyond a predefined limit, this system triggers the tracker to move into a safe position. These thresholds might vary according to the site location, and the company doesn’t specify them. Each row has a built-in torque-limiting clutch at the driving point. The clutch engages only when the wind-induced torque exceeds the preset limit, allowing the affected row to rotate to its maximum tilt angle, or stow position. However, ARRAY didn’t disclose the range of passive wind stow angle. Despite being mechanically linked by the driveline, this feature, available on a row-to-row basis, enables only the affected rows to enter the stow position. The exterior rows of a utility-scale PV tracker array, switched to passive stow position, act as a protective barrier for the inner rows. Following the high wind events, all passively stowed rows will realign with the rest of the normal operational tracker inside a block within 24 hours, added Array.
In addition to outlining the passive stow mechanism, the white paper offers a brief comparison with the active stow alternative. Unlike the active mechanism, which depends on remote monitoring and controllers, passive stow is based on a mechanical fail-safe design. While the active method places an entire block in stow position, the mechanically operated passive system can stow only the affected rows, thereby reducing potential energy losses.
The company stated that its tool, using high-resolution wind data for Kern County, California, simulates different stow strategies and calculates the energy losses for a 200 MW project. The comparative analysis of test results for a project lifespan of up to 30 years indicates that the passive stow strategy lowers the average energy losses to 0.05% compared to 2.8% with the active counterpart. These inferences were further substantiated by DNV, a 3rd party certification agency, noted ARRAY.
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