Mandalay Bay
SUNORA ENERGY SOLUTIONS / NRG ENERGY
MGM RESORTS INTERNATIONAL
Racking System: RoofMount | RM10
Structure Type: Large Commercial
Location: Las vegas, Nevada
Completed: Spring 2015
Challenge
MGM Resorts International (NYSE:MGM) in 2014 was solidifying its position as a leader in renewable energy and wanted to make the bustling Mandalay Bay a showcase. The site presented several roof elevations in six sections, including some with heights of 115 feet, and as a functioning convention center—one of the busiest in the country—could not pause while work was performed. In addition, Clark County’s planning authority is known for its exacting approach, so designs needed to be letter-perfect.
Solution
Unirac, with its 22-year history in solar, had been one of the first in the industry to make engineering a central focus, and this experience was brought to bear. Several completed designs for Mandalay Bay were considered and discussed, including one that was fully ballasted. In the end, the project used a hybrid design with limited ballast but no penetrations thanks to adhered attachments.
Wind analysis was complex due to extreme wind conditions. To meet code, some sections were analyzed as exposure B while others were treated as exposure C based on prevailing winds. Parapets and other factors made the analysis even more complicated. As one Unirac team member said, “everything on that job was custom.” High standards of engineering had to be met while creating designs that could actually be built given the constraints of the location. Unirac’s team delivered throughout.
The customer also needed a very precise CAD layout in order to survey the roof and coordinate attachments. Unirac was on site at a number of points to offer best practices and real-time field analysis.
Implementation
In interviews, the owner and installers spoke of the logistical challenges of working in one of the busiest areas in the United States, an active convention center on Las Vegas Boulevard. Materials couldn’t be staged at the site–point loads on the roof meant they couldn’t be hauled up all at once, either–so they had to arrive exactly as needed. Guests’ stays couldn’t be affected by noise or safety issues. Unirac was able to work with all the teams involved to deliver materials as and when needed (work was timed to coincide with periods of reduced traffic, e.g.).
THE PLANNING ON THE FIRST PHASE AND THE ACTUAL CONSTRUCTION OF THE ARRAY WAS ONE OF THE MOST PROBLEM-FREE PROJECTS I’VE OVERSEEN. IT WAS CARRIED OUT REALLY WELL.
Cindy Ortega, Senior Vice President and Chief Sustainability Officer of MGM Resorts International
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.
