3.4 MW Warehouse Project
Racking System: ECOFOOT 2+
Structure Type: LARGE Commercial
Location: NORTH CENTRAL, CALIFORNIA
Completed: OCTOBER 2020
Challenge
Not many single flat roofs can hold 3.4MW worth of solar panels, but this one in the Central Valley of California can. Unirac’s customer needed to deliver maximum value to minimize costs for the owner. The project also had total system weight requirements to hit and a need to keep attachment counts low. The system also required FM Global insurance approval, which involves a stringent upfront scrutiny of engineering rationales.
Solution
The Unirac sales team flew to the site early in the design phase to walk the roof with the contractor, a top-tier commercial contractor that knew EcoFoot from previous installations. The group talked through all of the details, and Unirac worked with the project principals to make materials, labor costs, and engineering requirements part of their overall evaluation. The superior installation speed and consequent labor savings of 10-degree EcoFoot 2+, plus the extensive planning support and insight from our team, became deciding factors.
Implementation
The final design required extensive engineering work. Though seismic requirements were not extreme, expert analysis was required to hit code requirements when considered as a total system weight. Approval had to be obtained from FM Global insurance, requiring input, rigorous testing work, and validation from nearly every
department at Unirac. Careful coordination and Unirac’s unparalleled engineering experience smoothed the process.
In addition, the roof’s large drainage pattern (“crickets”) raised questions for designers. Unirac engineers went into the lab to verify that EcoFoot clamps could accommodate up to 2.5 degrees of incline on each side. The testing helped project designers allow for significant differences in roof slope across the large area.
Designers wanted to use 72-cell, 385W LONGi modules for the project, and so Unirac assisted the contractor in getting the modules tested and certified for use with the 2+ system, performing the work in-house in Boulder thanks to its designation as a SolarPTL satellite 2703 certification facility.
Unirac was involved at each step of the installation. Installer Sales Specialist Reggie Espitia visited the site, for instance, to advise on detailed best practices, giving the contractor and developer peace of mind that their installation was proceeding without complication.
Benefit
The project definitely became a showcase. MGM demonstrated its leadership and the project was hailed as a watershed in which large-scale commercial solar was proven to be economically viable. Luminaries including President Barack Obama visited the site, which was touted as one of the largest and most innovative rooftop projects ever seen. MGM was quoted in the press as saying the PV system gave them resiliency against power losses while reducing their demand on the grid.
Hanwha (QCell and SolarOne) and Canadian Solar panels were ultimately installed on nearly 23,000 RM10 bays to create a 6.4MW system. More than twenty acres of rooftop were covered.
The system also became one of the first large projects to demonstrate the efficacy of bonded arrays for UL certification purposes.
