High-concentration planar microtracking photovoltaic system exceeding 30% effciency

Prospects for concentrating photovoltaic (CPV(power are growing as the market increasingly values high power conversion effciency to leverage now-dominant balance of system and soft costs. This trend is particularly acute for rooftop photovoltaic power, where delivering the high effciency of traditional CPV in the form factor of a standard rooftop photovoltaic panel could be transformative. Here, we demonstrate a fully automated planar microtracking CPV system <2 cm thick that operates at fixed tilt with a microscale triple-junction solar cell at > 660X concentration ratio over a 140 degrees full field of view. In outdoor testing over the course of two sunny days, the system operates automatically from sunrise to sunset, outperforming a 17%-effcient commercial silicon solar cell by generating > 50% more energy per unit area per day in a direct head-tohead competition. These results support the technical feasibility of planar microtracking CPV to deliver a step change in the effciency of rooftop solar panels at a commercially relevant concentration ratio.