While flat-plate silicon photovoltaics dominated the 1GW market for solar generation of electricity in 2004, significant opportunities exist for concentrator systems, including concentrator PV and solar-thermal-electric systems. All of these rely on the same basic principle, in which light is concentrated to a central receiver using mirrors or refractive optics. Concentrators require direct solar illumination, and the optics or mirrors must move during the course of the day to track the sun's trajectory. A key benefit of concentrator devices is in reducing the physical size of the receiver relative to the area in which the light is gathered. The area over which light is gathered for a given type of receiver ranges from a few centimeters for some PV concentrators, to meters or tens of meters for Stirling engines, to hundreds of meters for solar-thermal-electric systems. As detailed below, California is at the forefront of concentrator technology advances and is well positioned to reap the commercial benefits as concentrator approaches gain greater market share.
Elrod, S. A. Solar concentrators. Palo Alto CA: Palo Alto Research Center; 2006 February.