In Sydney, researchers working with readily available solar panels have converted over 40 percent of the total sunlight hitting the system into electricity.
“This is the highest efficiency ever reported for sunlight conversion into electricity,” Martin Green from the University of New South Wales (UNSW) says in a news release. This milestone was independently confirmed by the National Renewable Energy Laboratory in their outdoor test facility in the U.S.
The team used commercial solar cells, “but in a new way, so these efficiency improvements are readily accessible to the solar industry,” UNSW’s Mark Keevers adds. Traditional methods limit the conversion of sunlight into electricity to about 33 percent, AFP reports.
Their prototype uses sun-tracking mirrors to focus light on a tall building—called heliostat mirror power tower concentrators, Gizmag explains—and that sunlight is then split into multiple different solar cells. A key part of the design is the use of a custom “optical bandpass filter” that captures the sunlight that’s normally wasted by commercial solar cells on towers; these sorts of filters reflect certain light wavelengths while capturing others. As a result, the light is converted to electricity at an efficiency that’s higher than what the solar cells could achieve by themselves.
"The panels that you have on the roof of your home, at the moment they just have a single cell but eventually they'll have several different cells,” Green tells AFP, “and they'll be able to improve their efficiency to this kind of level.”
The prototype was developed by Australia-based RayGen, and some of the high-efficiency cells used were provided by U.S.-based Spectrolab. The work will be presented this week at the Australian PV Institute’s Asia-Pacific Solar Research Conference and will be published in Progress in Photovoltaics.