California, United States [RenewableEnergyWorld.com] Test results released this week reveal that a new technology from National Semiconductor Corp. can recover up to 57 percent of the power lost due to temporary or partial shading of solar photovoltaic (PV) panels.
In tests conducted at National’s Santa Clara, facility, a screen representing typical rooftop obstructions shaded a portion of a conventionally wired PV system. Although 8 to 16 percent of the array was shaded over the course of a day, it resulted in average power losses of between 35 percent and 40 percent. The company said that an identical solar array fitted with National’s SolarMagic power optimizers produced on average between 30 percent and 37 percent more electricity in the same conditions – effectively recouping up to 57 percent of the lost power.
“SolarMagic power optimizers have the potential to transform the solar market,” said Ralf Muenster, director of National Semiconductor’s Renewable Energy Segment. “This new technology tackles several problems that have long faced rooftop PV systems — shading and panel mismatch — and provides a viable solution to commercial customers and homeowners worldwide. Enabling the installation of solar arrays on roofs that were previously deemed unsuitable will also help the United States reach the ambitious renewable energy goals set by the Obama administration.”
For the testing, the test array and the reference array were each comprised of two strings with 12 PV panels per string. Both strings were attached to a Xantrex GT5.0-NA-240/208 inverter. The performance data was collected using Xantrex’s software, and had a measuring accuracy of +/- 5 percent.