RMI Publishes Top Recommendations for Building Hurricane-Resilient PV Systems

(Photo: Damaged solar panels on October 10, 2017, St. Thomas, US Virgin Islands. Credit: Jocelyn Augustino/FEMA)

Solar PV in the Caribbean is cost effective and provides reliable power generation, but the systems must be designed to survive devastating hurricanes, according to the Rocky Mountain Institute. RMI’s latest report details hurricane-resilient equipment specifications and procedures for designers, suppliers, and manufacturers.

The report, called “Solar Under Storm: Select Best Practices for Resilient Ground-Mount PV Systems with Hurricane Exposure,” dives into the root causes of PV system failures from hurricanes. It also makes key recommendations for how to build more resilient solar PV power plants.

“The 2017 hurricanes brought sustained wind speeds of over 180 miles per hour to many Caribbean islands,” the nonprofit’s blog says. “RMI sent expert structural engineering teams to the Caribbean region in fall 2017 to investigate why some PV systems survived virtually unscathed while others suffered extensive damage.”

Recommendations are organized into specifications and collaboration. Specifications that RMI suggests include:

• Using high-load PV modules (5,400 Pa)
• Requiring a structural engineering review and wind-tunnel report review
• Specifying a bolt hardware locking solution and bolt quality control process
• Specifying through bolting of modules as opposed to top-down or T clamps
• Requiring structural engineer review of lateral loads
• Not using self-tapping screws
• Specifying dual post pier foundations

For collaboration, RMI advises:

• Collaborate with module suppliers for implementation of static and dynamic load tests representative of Category 5 hurricane winds
• Collaborate with racking suppliers for full scale and connection test representative of Category 5 winds
• Collaborate with equipment suppliers to document material origin and certificate of grade and coating consistent with assumptions used in engineering calculations

“Perhaps the most opportune recommendation is for a regional and even international community of solar PV power plant stakeholders who have extreme wind exposure to regularly share lessons learned from new designs and extreme wind events,” the report says.

To help with that, RMI formed a PV Resiliency working group on the online Caribbean Renewable Energy Community (CAREC) hosted by the electric utilities association CARILEC.

“Fortunately, our island was not impacted last fall by the hurricanes,” Kendall Lee, managing director of Montserrat Utilities Limited, told RMI. “However, we are planning to add a considerable amount of solar PV to our power system over the next few years and we want to know how we can ensure the survival of these new assets.”

The full report is available here.