Shading a Problem for Solar Installers

Solar energy system owners and installers know that shading—shadows caused by chimneys, tree branches or dust—is a problem. How bad is the problem? National Semiconductor paid for a survey to quantify the issue, right before it’s due to start selling chips that it claims can recover some of the energy lost from shading.

The Santa Clara, Calif.-based company said the survey showed that 41 percent of solar installers have to deal with shading when they sell or install a system. Only a little over half of the surveyed, or 54 percent, said shading is not acceptable, suggesting that the issue might not be as dire as it seems. Greenberg Quinlan Rosner Research did the phone survey in January and spoke with 150 installers in the United States.

The amount of energy lost from shade can be significant, National Semi said. A panel can produce more than 50 percent less power if just 10 percent of it is in the shadow or covered in debris, the chip company said.

National Semi is proposing to fix this output problem with its SolarMargic branded power management chips. The chips would be attached to each panel to track the energy output and ensure that whatever a shaded panel can produce is harvested by the central inverter. In some current energy system designs, those shaded panels are bypassed, National Semi said.

The company delayed its launch to later this spring. Last year, the company said it would start selling the chips at the end of 2008.