SolarCity likes to be number one. The company already has by far the largest share of the U.S. residential solar market. It was also the first to securitize portfolios of rooftop solar assets. Not satisfied, it then went on to start work on the largest PV module factory in the Western Hemisphere at 1 GW of annual production.
Today, SolarCity announced that it will begin producing its first PV modules in small quantities at a 100 MW pilot facility, and is again claiming a superlative: That these will be the most efficient rooftop PV modules in production. The company reports a 22.04% module-level efficiency, as measured by third-party testing provider Renewable Energy Test Center.
However, not everyone agrees on SolarCity’s claim. While we were not able to verify efficiencies for Panasonic’s multi-junction HIT modules by press time, SunPower, which has held the record for this highest efficiency mass-produced crystalline silicon modules, told pv magazine that it has been shipping modules with greater than 22% efficiency to some of its customers.
"SunPower always welcomes others to the efficiency race," declared SunPower in a statement. "Its great that we all agree – efficiency matters."
SunPower has been one of the few companies to make a successful business out of producing high-efficiency PV. Like SunPower, SolarCity plans to produce these modules not only for the rooftop market, but also for utility-scale projects.
SolarCity also claims that the module performs better than other technologies under high temperatures, and that it is able to reduce manufacturing costs due to its proprietary processes. The company got into PV manufacturing with its purchase of Silevo, and it is unclear if these processes were acquired or developed after the acquisition.
SolarCity notes that while the new modules are being produced at its pilot plant, that it expects to produce modules with similar efficiency at its factory under construction in Buffalo, New York. This will be the largest PV module factory in the Western Hemisphere when complete.
Note: This article was modified on October 4, following an email conversation with SunPower in which the company verified that it has been shipping modules with greater than 22% efficiency.