How Energy Is Produced - The Renaissance of Renewable Energy - page 110

Figure 4.27. Concentrated PV plant. Most of the surface of the panel is occupied by
optical concentrators, thousands of small lenses, each focusing roughly 500 times the
sunlight onto a tiny high-efficiency multijunction photovoltaic cell. A Tesla Roadster
Electric Vehicle is parked beneath for scale. Source: Mbudzi at Wikimedia Commons.
Figure 4.28. An experimental solar airplane, built by NASA, and the International
Space Station, whose solar panels provide 110 kilowatts of power, roughly equivalent to
the requirements of fifty-five American households. Source: NASA ( www.nasa.gov ) .
From Cells to Plants
By the early 1960s, solar PV technology had advanced to the point where conversion
efficiencies were almost on par with modern commercial panels. Yet it took another three
decades for solar cells to be produced on an industrial scale. The reason for the delay was
cost. Solar cells are expensive to manufacture because the silicon they contain must be