Massachusetts Institute of Technology (MIT)

The use of flat-panel solar photovoltaics (FPV) is growing dramatically as costs decrease. By contrast, more efficient concentrated PV systems (CPV), which focus direct sunlight onto a single point, have not been widely adopted because of their high cost, large size, and expensive tracking systems. A new approach, micro-scale concentrated photovoltaic systems (micro-CPV), may deliver the cost and size benefits of conventional FPV systems, but with an estimated 50% performance improvement. Micro-CPV modules would use cost-effective trackers and generate more electrical power in a given area. This allows installation on space-constrained residential rooftops and decreased costs for commercial and utility applications. Finally, the MOSAIC systems would have the ability to capture both direct and diffuse sunlight, which could make CPV economical in more geographical regions. These innovations could spur the expanded use of PV to generate clean, renewable energy.

The Massachusetts Institute of Technology (MIT) with partner Sandia National Laboratories will develop a micro-CPV system. The team’s approach integrates optical concentrating elements with micro-scale solar cells to enhance efficiency, reduce material and fabrication costs, and significantly reduce system size. The team’s key innovation is the use of traditional silicon PV cells for more than one function. These traditional cells lay on a silicon substrate that has etched reflective cavities with high-performance micro-PV cells on the cavity floor. Light entering the system will hit a primary concentrator that then directs light into the reflective cavities and towards the high performance micro-PV cells. Diffuse light, which most CPV technologies do not capture, is collected by the lower performance silicon PV cells. The proposed technology could provide 40-55% more energy than conventional FPV and 15-40% more energy than traditional CPV with a significantly reduced system cost, because of the ability to collect both direct and diffuse light in a thin form factor.

If successful, innovations from MIT’s project may lower the cost of solar systems by allowing economical, high-volume manufacturing of micro-CPV arrays. Improved systems could encourage greater adoption of solar power in all three primary markets – residential, commercial, and utility.