#3. Face modules out of the wind at maximum tilt for hail resilience.
Array Technologies optimized its tracker’s defensive hail stow capabilities based on the results of VDE Americas’ hail risk advisory services. These third-party studies compared hail risk across various tilt-angles, facing both into and out of the wind. Based on these comparative risk assessments, Array Technologies realized that stowing modules at a maximum tilt angle facing away from the wind reduces the effective kinetic energy and damage potential of hail impacts. Informed by this catastrophic risk assessment report, Array Technologies was able to develop and implement a defensive stow protocol optimized for hail risk mitigation.
#4. Effective structural design accounts for both hail and wind.
Severe convective storm risk is not binary, as severe hail and high wind are coincident risks. According to NOAA, a severe thunderstorm produces hail greater than or equal to 1 inch (25 millimeters) in diameter and/or wind speeds greater than or equal to 58 miles per hour (25 meters per second). For effective risk mitigation, users must address the risks associated with both hail and wind. Since Array Technologies' linked-row trackers are capable of withstanding the full wind speed at a site, regardless of wind direction, project stakeholders do not need to choose between hail or wind stow during a severe storm.
#5. Automate tracker defensive hail stow to reduce project risk.
Since severe convective storm alerts may provide plant operators with little advanced warning, remote operation center protocols that rely on manual intervention could lead to a failure to stow in advance of a hail event. Array Technologies has developed automated hail response capabilities to address this vulnerability. DTN’s weather service data informs the automatic hail response, eliminating the need for manual intervention. This feature establishes a virtual geofence around the property. The controller will move all tracker rows to a maximum tilt angle if a severe convective storm crosses this perimeter.
#6. Be aware of severe weather risks during construction.
Depending on the size of the project, construction on a large utility solar project could range from six months to two years. If the support structure can withstand full site-design windspeeds at any tilt angle, have installers position each tracker row at a maximum tilt angle as soon as they install the glass. This defensive stow posture will mitigate against hail and wind damage before energization. VDE Americas’ catastrophic risk reports can characterize probabilistic storm approach distributions and optimal pre-energization tilt direction for any project site.