The world's largest solar plants sure look amazing, but for those with inquisitive minds they raise one big question: how the hell do they keep all those panels clean? Nowadays, using robots like this!

This video shows the newly installed robotic cleaning system at Ketura Sun Solar Park. Until now, the panels covering the 20-acre site were only cleaned about nine times a year—a laborious task, performed infrequently due to expense—which in turn led to sub-optimal plant efficiency.

Now, though, a robotic army—designed and made by Israel-based Ecoppia—swarm over the panels to keep them clean. The 100 centrally controlled automatons set to work at nighttime, using microfiber pads and controlled air flows to push dirt from the surface of the solar panels. The robots move up and down their own aluminum frames to avoid loading the panels, and during the day they sit at the bottom and charge using electricity generated by the plant. So, now you know. [Eccopia]