I don't know enough about pv's to know where the lack of efficiency stems from but last I heard solar panels were barely into the 20% range. These lenses are claimed to be 70% efficient but that says nothing about the potential for the panels themselves unless current optics are far below that level. I assume that current optics are lacking or they wouldn't be bothering with this line of research but even if the optics were to achieve 100% efficiency I'm curious what that would do to the total efficiency of a panel.