Zero energy devices (ZED): Stopping the increasing demand of electronics for grid-based electricity

Panel: 6. Appliances, product policy and ICT

This is a peer-reviewed paper.

Author:
Jim McMahon, Better Climate Research & Policy Analysis, USA

Abstract

The combination of technological advances in energy efficiency for electronic devices, coupled with advances in harvesting ambient energy, has the potential to achieve zero energy devices (ZEDs), self-powered and utilizing less than one watt each. The majority of energy-using devices sold globally are consumer electronics devices. While the energy consumption of each device is relatively small (a few to tens of Watts each), the rate of increase in their numbers has caused them to contribute a large increase in the demand for electricity. Technological advances are contributing to higher energy efficiency, often for the purpose of extending battery life. For example, computations per kilowatt-hour have doubled every 1.6 years since the 1940s. Battery life at constant computing power has increased 100 times per decade. More efficient designs of battery chargers could use 3-10 times less kWh per year. A newer and complimentary set of technological advances are raising the possibility for harvesting ambient energy and avoiding the use of grid-based power. Ambient energy is universally available (in magnitudes of 10s to 100s of milliWatts) and comes in multiple forms, including; a) radio waves (from broadcast communications and wireless networks); b) light (harvested by photovoltaic cells, which can currently capture about 10 mW per square centimeter); c) linear motion (e.g., kinetic energy from throwing a switch, captured as piezoelectric effect); d) temperature (e.g., temperature difference between a human body at 37oC and ambient air); and vibration (from walking or powered transport). Commercially available devices harvesting ambient energy exist in increasing numbers, including self-powered wireless light switches. This paper examines the future potential for designing ambient-energy harvesting into electronic devices (e.g., smart phones to portable computers and electronic readers to music devices) so that they are self-powered, zero energy devices (ZEDs).