Development of a 10 kW reflective dish PV system

A 10 kW reflective dish PV system is under development by SunPower Corporation. Two of these systems are designed for installation at the PVUSA (Photovoltaics for Utility-Scale Application, a consortium of utilities and public entities) test site in CA, USA. The PV modules are monolithic “dense arrays” of ten cells, fabricated and series/parallel connected on a single silicon wafer and mounted on water-cooled cold plates. The cells are point-contact backside silicon, currently of about 20% efficiency at 20 W/cm² [AM 1.5 D, 25 °C]. When recent techniques employed in producing smaller cells having 26% efficiency are incorporated, 23.5% module efficiency and 16% system efficiency are projected. The mirrored dish is comprised of 0.3048×3.048 M (1×10 ft) curved strips of second-surface low-iron glass mirrors. The tracker is a conventional two-axis design. Focal length is 8.5 m (28 ft); concentration is 250×. A 1/3-scale 1 kW prototype dish has been built and is undergoing testing at SunPower. This system has demonstrated 13% conversion efficiency at PVUSA rating conditions. Receiver modules are being designed to be applicable in larger central-receiver projects