Concentrator Photovoltaics: Not Just Solar Cells
Mar 18, 2015
ABOUT THIS WEBINAR
An efficiency of 46 percent has recently been achieved with four-junction solar cells under a concentration on the cell of 508 times the normal solar power flux on the Earth’s surface. Such high efficiencies are the driving force for the development of the concentrator photovoltaic (CPV) technology.
But solar cell efficiency is not the only factor. To be cost-effective, a CPV system requires optical elements that, properly mounted, cast enhanced solar power on the cells. The cell mountings must be able to dissipate the heat of the power not converted into electricity without reaching unacceptable temperatures. They have to be mounted on trackers that keep the cells in focus during the sun’s journey across the sky. All these requirements have to be met in a cheap industrial way and produce large surfaces.
Dr. Antonio Luque is an emeritus professor at the Polytechnic University of Madrid and founder of its Solar Energy Institute. He is also affiliated with the Nanostructured Solar Cells Laboratory Ioffe Institute in St. Petersburg, Russia. The inventor of the intermediate-band solar cell, he holds about 20 patents and has about 1000 Web of Science citations. He has been honored with several important distinctions, among them the Böer Solar Energy Medal from the University of Delaware.
Additional Questions and Answers
Despite high efficiency of multijunction cells, the cost of land or roof-top area is 1/Cos(Zenith,max angle) compared with fixed flat-panel silicon? For Zmax = 75° (10-hour solar day) “installation area” (land/roof) cost is 3.8× greater! Isn't this the major CPV detractor?
CPV is usually oriented to power plants.
In such case the price of the land is negligible. To support this statement see the ground coverage ratio (GCR: area of modules divided by area of land) of real plants around the world. All these plants are fixed excepting the one of Moura with 2 axes tracking (this is applicable to the case of concentrators). The GCR of the latter is much lower (more land is needed). However, in theory flat modules may be built with a GCR as big as 0.5; however it is about half of it. Very generous lad is used for servicing, proving my statement.
For roofs you may be right (I think the trade-off may be borderline). Anyway, I do not recommend to put CPV on roofs.