...AND CHEAPER...:

 Researchers from Penn State University and the University of Illinois have developed a smaller, consumer-sized CPV system that gets around some of the normal disadvantages of CPV and maximizes its advantages. Though at an early stage, it could allow homeowners to buy into higher-efficiency cells by reducing the cost of tracking.

The system has two main innovations. First the cells, which were developed at the University of Illinois, are very small: only tenths of a millimeter across compared to cells that are normally centimeters-squared. Second, the tracking system reverses the way things are normally done. The "microcells" are laid onto a piece of plastic, then sandwiched between two bubbled layers of optics. During the day, the middle layer moves slowly against the static outer layers, so it's always got enough light.

"Instead of pointing all your optics at the sun, all your optics remain fixed and the solar cells move to follow the focal point," explains Chris Giebink, an assistant professor of electrical engineering at Penn State.

As yet, the technology has only reached the prototype stage. But the results so far are impressive. The system captured 70% of available optical light and generated 50% more power than a conventional silicon solar panel (which has efficiency of about 20%).

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