Results from a multi-year performance comparison by Sandia National Labs reveal that Stion’s “Simply Better” CIGS technology outperformed mono-crystalline by as much as 6%. Testing was completed at three climatically distinct US DOE Regional Test Centers (RTCs) in NM, FL and VT.
In the test, Stion’s modules outperformed expectations by 1 percent based on their nameplate power ratings. In contrast, the c-Si reference arrays at the RTCs underperformed by 5 percent relative to their rated power. The study which is based on the “relative efficiency” or performance relative to the nameplate rating of the modules began in January 2014 and was lasted two years.
Not only do the Stion modules slightly outperform their rated capacity but, as irradiance-the amount of sunlight hitting the panels-increases, the efficiency of the Stion modules also increases, which is not generally true of c-Si modules.
Stion modules also offer an advantage in northern regions. In Vermont, Sandia observed that Stion’s frameless modules shed snow faster than the adjacent monocrystalline framed modules. Stion has observed the same phenomenon in other snowy regions. The accelerated shedding is due to the frameless configuration, which allows snow to slide off the panel without obstruction and also to the panels’ black aesthetics, which result in snow melting faster once the sun reappears after a storm. This translates into an increase in energy production and therefore a higher return-on-investment.”It’s important for companies to have a good understanding of how weather will impact their products over time. The RTC collects and analyzes high-quality data to give U.S. companies such as Stion the information they need to ensure their products perform well in a variety of climates,” says Joshua Stein, a Sandia photovoltaics researcher and director of the RTC program.
The US DOE RTC program, which is funded though the DOE’s SunShot Initiative and managed by Sandia for the DOE, aims to increase innovation in the US solar sector by rigorously evaluating the performance and reliability of new solar technologies across multiple climates. Stion was accepted into the program in 2014 and agreed to install systems in New Mexico, which represents a hot, arid climate; Florida, which is hot and humid; and Vermont, which has harsh snowy winters. The Stion systems installed at each site had identical data-monitoring systems, which were designed by Sandia, and rigorously monitored.
US manufacturers that wish to have their equipment validated at one or more RTCs are selected via a competitive process and work closely with Sandia and/or the National Renewable Energy Laboratory on an installation and validation plan, which the RTCs then execute. For more information on the RTC program, see rtc.sandia.gov.