According to an article by Richard Gray on The Telegraph from 8 May 2011, Korean researchers are working on developing a way to capture the residual mechanical energy that is created when a person is talking on their cell phone and use it to charge the battery.
From the middle of the piece:
The technology would also be able to harness background noise and even music to charge a phone when not in use. However, there could be a downside to the innovation, if it gives people a new reason to shout into their phones as they attempt to squeeze in every extra bit of power they can.
The influx of nanotechnology, specifically nanotubes and their potential for superconductivity, adds a ton of possibilities to the conversation about green energy. It doesn’t get more renewable than the power of a young person’s voice. However, it does seem like the amount of mechanical energy released during a typical cell phone conversation would be quite small.
In the meantime, at least we have our solar chargers.