Ultra-high efficiency solar cells similar to those used in space may now be possible on your rooftop thanks to a new microscale solar concentration technology developed by an international team of researchers.
“Concentrating photovoltaic (CPV) systems leverage the cost of high efficiency multi-junction solar cells by using inexpensive optics to concentrate sunlight onto them,” said Noel C. Giebink, assistant professor of electrical engineering, Penn State. “Current CPV systems are the size of billboards and have to be pointed very accurately to track the sun throughout the day. But, you can’t put a system like this on your roof, which is where the majority of solar panels throughout the world are installed.”
Giebink notes that the falling cost of typical silicon solar cells is making them a smaller and smaller fraction of the overall cost of solar electricity, which also includes “soft” costs like permitting, wiring, installation and maintenance that have remained fixed over time. Improving cell efficiency from about 20 percent for silicon toward greater than 40 percent with multi-junction CPV is important because increasing the power generated by a given system reduces the overall cost of the electricity that it generates.
To enable CPV on rooftops, the researchers combined miniaturized, gallium arsenide photovoltaic cells, 3D-printed plastic lens arrays and a moveable focusing mechanism to reduce the size, weight and cost of the CPV system and create something similar to a traditional solar panel that can be placed on the south-facing side of a building’s roof. They report their results today (Feb. 5) in Nature Communications. … (read more)