Solar Under Storm III: Updated best practices for resilient ground-mount PV systems with hurricane exposure

The report identifies critical failure modes in ground-mount solar PV systems exposed to extreme winds, such as the failure of top-down clamps and low-cycle fatigue in module frames. It recommends high-load modules (4,000 Pa uplift), through-bolting with specialized washers, and dual-post foundation designs to improve survivability in hurricane-prone regions.

• Field investigations after Hurricane Beryl in the Grenadines revealed a stark contrast in survivability between projects that implemented Solar Under Storm best practices and those that did not.
• Common root causes of solar system failure during extreme wind events include the use of shared top-down or T-clamps, undersized or improperly designed racking, lack of lateral support, and the use of self-tapping screws instead of through-bolting.
• A critical 'lurking failure mode' identified is low-cycle fatigue of PV module frames, where cyclical dynamic loading causes failures even when wind speeds are below the static load rating. This is exacerbated by modern frames having thinner bottom flanges (as low as 1.1 mm).
• Systems that survived extreme winds typically featured dual-post piers, through-bolting of modules (avoiding clamps), lateral racking supports, and vibration-resistant connections such as Nyloc nuts.
• The report recommends specifying high-load PV modules with a 4,000 Pa uplift rating based on structural calculations rather than just manufacturer datasheets.
• To mitigate low-cycle fatigue, the report recommends using specialized backing plates, such as the StormPlate™, which can increase cyclical loading failure cycles by approximately 450 times compared to standard round washers.
• Failure to account for the topographic factor (Kzt) in wind design can lead to significant underestimation of wind pressures, particularly for arrays located on hilltops, ridges, or escarpments.
• The report advises against the use of solar trackers for projects located in wind zones categorized as Category 3 or higher.

APA

Burgess, C., Oudheusden, F., Needham, C., & Neverson, F. (2025). Solar Under Storm III: Updated best practices for resilient ground-mount PV systems with hurricane exposure. RMI. https://rmi.org/app/uploads/dlm_uploads/2025/06/rmi-june-2025_islands-solar-under-storm-III.pdf

Chicago

Burgess, Christopher, Frank Oudheusden, Chris Needham, and Fidel Neverson. Solar Under Storm III: Updated best practices for resilient ground-mount PV systems with hurricane exposure. RMI, 2025. https://rmi.org/app/uploads/dlm_uploads/2025/06/rmi-june-2025_islands-solar-under-storm-III.pdf.

Wikipedia

{{cite report |last1=Burgess |first1=Christopher |last2=Oudheusden |first2=Frank |last3=Needham |first3=Chris |last4=Neverson |first4=Fidel |title=Solar Under Storm III: Updated best practices for resilient ground-mount PV systems with hurricane exposure |publisher=RMI |date=June 2025 |url=https://rmi.org/app/uploads/dlm_uploads/2025/06/rmi-june-2025_islands-solar-under-storm-III.pdf |access-date=23 October 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{burgess2025solar, author = {Burgess, Christopher and Oudheusden, Frank and Needham, Chris and Neverson, Fidel}, title = {{Solar Under Storm III: Updated best practices for resilient ground-mount PV systems with hurricane exposure}}, institution = {RMI}, year = {2025}, month = jun, url = {https://rmi.org/app/uploads/dlm_uploads/2025/06/rmi-june-2025_islands-solar-under-storm-III.pdf}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }