"ENERGY: Power-harvesting technology enters phase two"

Many years of innovation in power harvesting have brought some maturity to solar, wind, geothermal and even wave technologies. Solar panels have become ubiquitous, General Electric has mastered the megawatt-caliber wind and geothermal turbine, and younger companies like Finavera Renewables have harnessed ocean-wave motion with electrical- generator technologies. On the horizon, however, is a new wave of power harvesting. A variety of technologies eliminate the need for batteries through the use of innovative transducers that generate electricity by virtue of converting the linear motion of pushing a button, the vibrations on an aircraft, the fluctuations of a magnetic field, the radio waves that fill the air and ever-present environmental gradients such as changes in temperature.
Text: http://www.eetimes.com/showArticle.jhtml?articleID=198702232