Utility-Scale PV Ground-Mount Racking Solutions
Inside this Article
The utility-scale PV market has significantly transformed over the last 5 years. Whereas 1 MW–5 MW ground-mounted projects were considered large a few years ago, fixed-tilt and tracking systems are now deployed in projects over 100 MW.
Utility-scale ground-mounted projects range from less than a megawatt to several hundreds of megawatts. Project developers deploy both fixed-tilt and tracking arrays. Foundations for some projects may penetrate the earth or require excavation, whereas other sites may require less-invasive solutions or a combination of approaches.
Product designs and solutions continue to evolve to reduce installation time for the racking system and modules. These technologies can include preassembled components and parts (including racks or small groups of modules), integrated grounding solutions and higher tolerances for foundation-to-rack connections. Many manufacturers are moving to steel and away from more-expensive aluminum. Racking systems may be ARRA compliant, listed to UL 2703 or UL 3703, and certified by third-party agencies to meet wind, snow load or other code requirements. (UL 3703 is the tracking system equivalent of UL 2703 for fixed-tilt systems.)
For large projects, most racking manufacturers offer services including geotechnical studies, system design and engineering, bonding certification, off- and on-site construction support, project management and complete EPC services. Manufacturers provide varying warranties with optional extensions to meet project needs or timelines.
To better understand the current utility-scale ground-mount racking options for fixed and tracked arrays, I contacted manufacturers and EPC contractors who specialize in this sector of the PV industry. We discussed trends, features, design and best-practice considerations.
How have utility-scale ground-mount racking systems changed in recent years?
“Some racking systems have become more efficient from a construction perspective—fewer parts and tools required. Several new racking companies have entered the market, which is great for the industry. However, many of the newer systems are not nearly as elegant as evolved designs from a veteran racking manufacturer. The creation of UL 2703 has been key for decreasing installation time while reducing the number of EGC terminations and potential failure points.”
—David Del Vecchio, senior engineer, Strata Solar, stratasolar.com
“Utility-scale ground-mount systems have moved away from welded connections and replaced them with fasteners. In addition, foundation techniques that utilize less concrete have become available to help reduce material costs. From a construction standpoint, the system designs are more adaptable to sloped terrain and utilize preassembled components, helping reduce labor time in the field.”
—Jason Grissom, construction manager, SunEdison, sunedison.com
“In recent years, tracking companies have gone to great lengths to improve the quality and cost of these technologies. Trackers are more reliable, more durable and more cost effective than ever before, and we’re seeing these improvements pay off as the global market for trackers continues to expand.”
—Jay Johnson, VP of business development, Exosun, exosun.net
“Utility-scale racking systems have moved toward using mono-post designs and fewer parts to reduce installation time and cost. Improved post designs, such as a channel with return and increased contact surface area, reduce embedment-depth requirements. In addition, manufacturers are replacing aluminum with galvanized steel to reduce material costs.”
—Andrew Barron Worden, CEO, GameChange Racking, gamechangeracking.com
“Racking systems of all types are becoming more advanced, with integrated features such as wire management, automated grounding and preassembly becoming more prevalent. All of these features are intended to help drive down BOS, labor and soft costs, therefore resulting in more-profitable installations for developers, installers and EPCs.”
—Steve Daniel, EVP of sales and marketing, Solar FlexRack, solarflexrack.com