Green Energy

Many commercially installed panels are around 21% efficiency. That's up from about 18% even ten years ago. There are panels that dramatically higher in conversion, but they tend not to be cost-effective or capable of lasting. Wikipedia has an article on it, and a chart that show the highest research cell NREL has tested is 47.6%. To quote "They reach their highest potential when the incoming sunlight is concentrated by lenses onto miniature solar cell devices of just a few square millimeters in size." So not production ready nor large deployment.