"However, manufacturers continuously improve their production processes and it is likely that SunPower has been able to incrementally improve the initial reported efficiency," Ogden said.
Solar panel manufacturers are pushing the limits of efficiency gains, pursuing improvements and technologies that yield an increase of a few tenths-of-a-percent, Ogden said.
Incremental gains in efficiency increase the value of the solar panel, enabling it to produce more electricity over the panel's lifetime.
"SolarCity's achievement of a 22% efficient panel is significant, but even more valuable is their claim of producing 30%-40% more electricity than a standard panel at the same size," Ogden added.
SolarCity's new panels use the same photovoltaic cells as its previous model panels, but the company's engineering team was able to squeeze more photovoltaic cells into the same area and arranged them to minimize energy loss, according to Ben Heng, SolarCity's senior vice president of product engineering.
"It's all fine and good and fundamental to work on the solar cell technology, but sometimes we forget there is low hanging fruit or less fundamentally challenging methods to improve the overall efficiency of the product," Heng said. "In this case it was the packaging."
SolarCity also claims its panels don't suffer efficiency losses due to increases in temperature to the degree that other panels do.
"That was a claim that had previously been monopolized by thin-film modules, like those produced by First Solar and SolarFrontier," Ogden said. "That could be a key differentiator in hot climates."
SolarCity initially expects to install the new panels on rooftops and carports for homes, businesses, schools and other organizations, but it will also be excellent for utility-scale solar fields and other large-scale, ground level installations.
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