Several users sent links to a recent Science Daily story on the development of wireless energy transmission technology by Marin Soljačić of MIT. While the media is hyping its use for powering handheld gadgets such as cellphones, it could be more useful for powering robots. The technology works on the same principle of induction that allows transformers to work but, in this case, the induction operates over larger distances. For details on how the process works as well as suggestions for application in the field of MEMS and nano-robotics, see the paper, "Wireless Non-Radiative Energy Transmission" (PDF format). Oddly, Science Daily says, "non-radiative energy transfer is a novel application no one seems to have pursued before". Apparently, they forgot that Nikola Tesla spent a good part of his life demonstrating and patenting wireless power transmission techniques including some based on what he called "electrostatic induction".