Sandia National Laboratories’ researchers recently hosted Darin Palmer, CEO of Rocking Solar, for a demonstration of his potentially game-changing approach to populating commercial rooftops with solar. The two-day visit in late July offered Sandia Photovoltaic Systems Evaluation Laboratory (PSEL) scientists and Sandia Experimental Solid Mechanics engineers an up-close look at the new system.
“Sandia continues to support innovation in the US sector in lockstep with the Solar Energy Technologies Office’s goal of driving down the costs of solar-generated electricity through improvements in efficiency and reliability,” said Sandia photovoltaics researcher Laurie Burnham. “To that end, we are working with companies through the American-Made Solar Prize to support innovative concepts and experimental designs that show promise to achieve significant cost reductions and accelerate wide-scale deployment.”
Rocking Solar is a Round 4 Finalist in the U.S. Department of Energy’s American-Made Solar Prize, in the running for its patent-pending design, which eliminates the need for load bearing and penetrating ground-mounts, and reduces costs and parts for a single-axis tracker. This innovation makes the system ideal for low-slope commercial rooftops, capped landfills, and other plots where ground penetrations are not desirable.
“The American-Made Solar Prize has given us a significant jump-start in our development and commercialization efforts,” Palmer said. “Sandia testing was critical to ensure Rocking Solar design meets commercial rooftop requirements of wind uplift, dynamic wind pressures, snow load, seismic, and electrical grounding. Thanks to Sandia and [others], we are confident we can deliver a best-in-class solution.”
Single-axis trackers, which follow the sun as its vertical position in the sky changes relative to a fixed surface, typically increase solar generation from 25 to 35 percent, but at a higher cost than fixed-tilt solar arrays. Unlike fixed-tilt solar arrays, which don’t move, tracker systems require control systems and a heavy-duty support structure that enables solar panels to rotate along an axis, even under heavy wind loads.
According to Palmer, Rocking Solar’s novel design outcompetes traditional single-axis trackers when it comes to commercial rooftops, where weight, flexibility, and cost are paramount concerns. The Rocking Solar approach eliminates the need for heavy-duty motors and relies instead on the momentum of a rocker controlled by a simple actuator. The result is a high-efficiency tracker that weighs less, costs less and has lower risk (i.e., less potential for roof damage), and therefore has the potential to open up thousands of acres of warehouse and other commercial rooftops to solar, bringing electricity generation close to demand.
“Sandia was not there just to test our system but to discuss improvements and considerations for our design; from the technical staff to managers, they were all engaged in making it a great experience for Rocking Solar,” Palmer said.
Like other single-axis tracker designs, Rocking Solar generates up to 30% more energy per panel, relative to fixed-tilt arrays, but is differentiated by the techno-economic advantages it brings to commercial rooftops, many of which are reflective, and therefore ideal for bifacial PV systems that further increase yield. With 30% fewer panels needed to meet energy output due to higher yield, the outcome can be a 22% cost drop for the same amount of energy. Most important, the Rocking Solar design requires less ballast and fewer penetrations relative to traditional tracker systems, translating into less risk and lower installation costs for site owners.
“Our support for Rocking Solar is a great example of cross-lab collaboration, involving the PSEL team, as well as Sandia structural engineers,” Burnham said.
“The American-Made Solar Prize opens up Sandia’s capabilities and expertise to help American industry,” Tony Martino, manager of the Photovoltaics & Material Technologies department said. “At the same time, we learn the newest technologies coming to market, and we meet the people. It is a great way to stay engaged in the community and develop partnerships that can last for years.”
The winners for Round 4 of the American-Made Solar Prize will be announced in September. If Rocking Solar wins, they will spend some of their prize money on a demonstration project at the Nevada Regional Test Center, with technical support provided by both Sandia and UNLV. The location of the site, just south of Las Vegas, was chosen, in part, to draw the attention of casinos and other owners of commercial rooftops in a top-ten state for cumulative solar capacity.
Learn more about the Sandia Photovoltaic Systems Evaluation Laboratory and the U.S. Department of Energy’s American-Made Solar Prize.
Read more about Rocking Solar.
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September 13, 2021