Decline of the Carrisa Plains PV power plant: the impact of concentrating sunlight on flat plates

The Carrisa Plains photovoltaic (PV) power plant located in central California has steadily degraded in performance since 1986 at a rate of approximately 10% per year. Originally rated at 5.2 MW, the plant routinely produced less than 3 MW as of 1990. The plant is composed of two-axis trackers with single-crystalline flat plate modules, and over 90% of the trackers have V-trough mirrors to concentrate sunlight. This low-concentration design has caused an accelerated browning of the modules and is the cause of the plant's decline. Electrical testing was performed to investigate the ramifications of module browning. The results indicate that ethylene-vinyl acetate (EVA) browning is an important concern for the PV industry and that low-concentration designs should not be used for one-sun flat plate modules until the issue has been resolved.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>