Energy Scavenging is a phrase I had never heard of until I started working with wireless sensor networks. The idea is to collect ambient energy and use it to power something, usually in the form of electricity. I thought the concept was still pretty obscure until I ran across it on the SciFi Tech blog, Green Week: 6 energy scavengers that get you power for free. Apparently this blog entry was part of NBC Universal’s Green is Universal promotion. Apparently last week was NBC’s Green Week where many of their shows had green themes. I guess I missed it, but ad least I ran across this interesting blog.

The article highlights 6 energy scavenging technologies:

1. Tate ambient power module: a module patented by Joseph Tate of California which converts radio-wave energy into electricity. It has the added potential bonus of being able to detect earthquakes.
2. Crowd farms: two MIT architecture grad students try to harvest the energy of many people walking and running, for example in a subway station.
3. Rooftop wind turbines: modular wind turbine array for installation on urban buildings designed by Aerovironment. I guess solar arrays would count too.
4. Waste heat capture: High Merit Thermoelectrics has a plan to harvest all that energy thrown off by truck exhaust systems and catalytic converters.
5. Capturing methane: Oregon-based natural gas provider NW Natural is capturing methane from cow manure, fighting global warming one cowpie at a time!
6. Power skin: IntAct Lab, in Cambridge, MA, has a motion-sensitive power skin concept that captures wasted motion.

In addition to those listed by SciFi, here are a few projects I am aware of:

1. GreenPeak Technologies: Ultra-low power wireless control networks with energy harvesting interfaces for battery free nodes.
2. EnOcean: Self-powered wireless sensors - Green. Smart. Wireless.
3. Perpetuum: Vibration energy harvesting technology enabling wireless and battery-free sensing.
4. East Japan Railway Company: As read on TreeHugger’s Japan: Producing Electricity from Train Station Ticket Gates using piezo elements to collect energy as commuters walk through.