Guys, anyone knows the sense of "measured at a concentration of 297 suns."? is sufficient much less energy to transform the earth in a giant BBQ.
A rough rule of thumb is that you get 1kW/m^2 of raw sunlight, so to get reasonable powers (in the MW+ range) out of a solar installation without needing an enormous solar cell budget, you need cheap concentrators of some sort.
If it's slightly cloudy, I could see efficiencies dropping to the single digits, as each of these cells is actually four different cells all wired in series, each sensitive to different wavelengths of light. If the blue drops out, the corresponding cell on the top of the stack acts as a resistor (and it can even burn out, being so thin).
Solar cell efficiency records (particularly for concentrator applications) are like discovering new transuranic elements- extremely useful and interesting at first, then significantly diminishing returns.