Silevo continues to make solar panel performance breakthroughs.
First, Sandia National Laboratories measured the proprietary tunneling junction cell architecture at a 22.1 percent cell conversion efficiency, up from its previous best of 21.4 percent. Business Development and Marketing VP Chris Beitel says this puts the Silevo modules in an efficiency category matched only by SunPower (NASDAQ:SPWR) and Sanyo (NYSE:PC) among crystalline silicon-based products.
Beitel said Silevo’s “hybrid solar cell concept” is cost-competitive with those manufacturers because it “couples the best attributes of materials characterized in solar and other industries for many years.” It has “a crystalline silicon substrate,” “an oxide layer,” “an amorphous silicon layer like that used in thin-film silicon solar technologies,” and “a copper-based metallization scheme," Beitel explained.
Silevo’s second performance achievement was earning a 93.5 percent PTC-to-STC ratio in the California Energy Commission (CEC) December rankings, the top number for the 295 watts-peak category. The ratio measures what part of the standard test conditions (STC) rated power a module can produce under the higher temperature conditions (PTC) it would likely face after long hours in the California sun.
A number of other manufacturers’ modules in the CEC’s 295 watts-peak rankings approach Silevo’s number, notably Suntech (NYSE:STP) (92.8 percent), SunPower (91.9 percent), and Trina (NYSE:TSL) (91.8 percent). But, in calling Silevo’s ratio “impressive,” PV Evolution Labs CEO Jenya Meydbray noted that “every fraction of a percent matters.”
Finally, the Triex module’s performance in the Renewable Energy Test Center's (RETC) cutting-edge Potential Induced Degradation (PID) testing was matched by only one other manufacturer’s modules, according to RETC VP Cherif Kedir. Silevo’s panels endured 1,500 hours of testing before losing power output and performance degraded beyond 5 percent only after 2,000 hours of testing. Few other modules were tested as many as 200 hours.
The PID rating measures a module’s performance if it is grounded in a manner not compatible with the system.
Renewable Energy Testing Center (RETC) VP Cherif Kedir called the Silevo PID test performance “pretty significant.” As part of an NREL-chaired panel to establish an industry-wide PID standard, he pointed out that Silevo’s RETC-conducted 2,000-hour test exceeded the proposed 96-hour standard and the temperature conditions were more demanding.
The proposed PID standard test would subject a panel in a 60-degrees-Celsius, 85-percent-humidity chamber to a voltage bias caused by incompatible grounding. RETC’s test put Silevo’s module in an 85-degrees-Celsius, 85-percent-humidity chamber and subjected it to a 1,000-volt bias.
“The reason the Silevo results are important,” Kedir explained, “is that of the close to 100 panels we have tested, some die off -- that is, lose 5 percent of their power output -- as early as 50 or 100 hours [into the testing]. The majority stay on for 200 or 300 hours.” Only one other panel, he said, matched the Silevo panel’s 1,500-hour performance.”
Meydbray said his lab typically tests for 600 hours and has found that modules either fail within 50 or 100 hours or show little degradation over the test period.
In 95 percent to 98 percent of cases, where a module’s grounding is compatible with the system in which it is configured, Kedir acknowledged, “you would never see this problem.”
There are other parameters important to the choice of a module, such as the quantification of how light induces degradation and how the angle of sunlight alters power output. And there is the question of the cost of the power.
“The solar space is stressed, but our belief is that it comes down to product value and product differentiation,” Beitel said, and these ratings and measurements differentiate the Silevo product by affirming its high value.
Beitel said the marketplace has also affirmed that value. “We have a 32-megawatt line in China and we are oversubscribed,” Beitel said. “The executive team is out right now surveying the next sites for manufacturing expansion. Our plan is to make a site selection, raise the necessary capital and expand our operations by 200 megawatts next year.”
Meydbray said that assessing a module’s quality, something increasingly vital to those who are being asked to put tens or hundreds of million dollars into solar projects and solar funds, is very complicated and necessitates a wide range of tests.
Silevo still must prove its real-world performance and find acceptance among customers. Or, as Beitel put it, “assemble installations, and work on bankability issues, and show performance and get validation of it, and show energy harvest benefit.”
Tags: california energy commission, cell architecture, crystalline silicon, module, pid, potential induced degradation, ptc, ptcstc ratio, pv evolution lab, renewable energy test center, retc, sandia national lab, sanyo, silevo, stc