Witricity

Electricity is an integral part of our lives, and we need it to power many of the objects in our life. Nikola Tesla first thought of transmitting this energy through the air. He planned to build large towers on the world that would transmit energy and power devices all around the globe. Unfortunately, it didn't work out to well and was never seen to completion. Since then, wires have been the status quo and we have accpeted them, along with batteries, as our energy providers. Yet, why has this become the norm, when batteries are bulky and only have a limited lifetime and wires are a tangled mess and a nuisance. In the past few years, new wireless technologies have been advanced but they were not ideal. First there is transferring with radio waves, which has been shown to work at very large distances. However, they don't provide a lot electricity; not enough to power most appliances. Charge pads have also come out, where a coil with a current will induce another near it to also have a current. This only works for small distances, i.e. inches, and dramatically loses efficiency as you move farther from the object.

A team at MIT decided to use magnetic resonance to achieve the wireless electricity goal. It was prompted because one of the researcher's wife's phone kept having a low battery beep during the night and it was waking up. To solve this problem, wireless electricity was born. 2 coils are used, just as the charge pads, but they work by different methods. Here, the coils are manufactured to resonate at the same frequency, allowing them to transfer energy very efficiently. This is very similar to an opera singer breaking a specific glass or aligning the frequency of you legs with a swing to get it started. When the frequencies are in sync, then the energy is transferred. The magnetic field caused by the first coil will only induce a current in the coil that has the same resonant frequency. Therefore, the energy is non-radiative because it doesn't do harm to anything with a different resonant frequency. Going back to the opera singer, only 1 glass will be shattered, while the rest will just sit there unharmed. Witricity holds many possibilities like eliminating cluttersome cords. Think of an airport with free wi-fi and witricity; there would be no plugs to fight over. This technology has already been proven to work, so hopefully in the next few years it will become commercially available and eventually the norm where we can look back at cords and laugh.

Here is a demo of Witricity and also an explanation.
http://www.ted.com/talks/eric_giler_demos_wireless_electricity.html