Solar Under Storm Part II

The report analyzes rooftop solar PV failures following major hurricanes in the Caribbean (2017-2019) to establish engineering and installation best practices. It identifies critical failure modes, such as top-down clip failures and corner overturning, and recommends specific technical mitigations including vibration-resistant hardware, mechanical attachments over purely ballasted systems, and strict adherence to roof edge setbacks. The authors estimate that implementing these resilience measures increases engineering, procurement, and construction (EPC) costs by approximately 5%.

• Analysis of 26 rooftop projects revealed four primary failure modes: top-down clip failure, debris/impact failure, corner overturn failure (specifically in ballasted/mechanically attached hybrid flat roofs), and racking connection failure. Top-down clip failure was particularly prevalent, occurring in 96% of applicable projects.
• The report recommends against using ballasted-only systems due to the high risk of cascading failures, advising that all systems utilize positive mechanical attachments to the building structure.
• To prevent module liberation, the report advises using top-down clamps that hold modules individually or independently, or utilizing through-bolting. It specifically warns against shared (middle) clips, which can lead to cascading failures if one module is lost.
• Proper installation layout is critical for wind resilience; modules should not overhang roof edges and should be limited to wind zones one and two, as wind pressure in zone three is approximately 50% higher than in zone two.
• The report identifies joint loosening caused by vibration as a major contributor to connection failure and recommends the use of vibration-resistant fasteners and the avoidance of self-tapping screws for structural connections.
• Implementing these resilience best practices is estimated to increase engineering, procurement, and construction (EPC) costs by approximately 5% compared to standard Category 3 or 4 rated installations.

APA

BURGESS, C., DETWEILER, S., NEEDHAM, C., & OUDHEUSDEN, F. (2020). Solar Under Storm Part II. RMI. https://rmi.org/app/uploads/2026/05/Solar_Under_Storm_Part_Two.pdf

Chicago

BURGESS, CHRISTOPHER, SANYA DETWEILER, CHRIS NEEDHAM, and FRANK OUDHEUSDEN. Solar Under Storm Part II. RMI, 2020. https://rmi.org/app/uploads/2026/05/Solar_Under_Storm_Part_Two.pdf.

Wikipedia

{{cite report |last1=BURGESS |first1=CHRISTOPHER |last2=DETWEILER |first2=SANYA |last3=NEEDHAM |first3=CHRIS |last4=OUDHEUSDEN |first4=FRANK |title=Solar Under Storm Part II |publisher=RMI |date=February 2020 |url=https://rmi.org/app/uploads/2026/05/Solar_Under_Storm_Part_Two.pdf |access-date=17 August 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{burgess2020solar, author = {BURGESS, CHRISTOPHER and DETWEILER, SANYA and NEEDHAM, CHRIS and OUDHEUSDEN, FRANK}, title = {{Solar Under Storm Part II}}, institution = {RMI}, year = {2020}, month = feb, url = {https://rmi.org/app/uploads/2026/05/Solar_Under_Storm_Part_Two.pdf}, urldate = {2026-08-17}, note = {Indexed by Climate Insights Directory} }