Here's a pretty cool example of energy harvesting: Greentech Media is highlighting VYCON Energy's REGEN crane system, used at cargo ports, which captures some of the energy from lowering shipping containers using a flywheel, and makes a serious dent in reducing the amount of diesel fuel these massive cranes consume:The cranes normally run on diesel generators 500-800 kw in size. Not only do they provide power to lift the shipping containers themselves, but also need to run while lowering the container, to ensure that the box is controlled on the descent. That's where the REGEN system comes into play.
The flywheel absorbs that energy and feeds it back into the system, allowing port operators to install smaller generators on the cranes. That results in reductions of diesel consumption of on average 30%, and in some cases up to 45%.
Even though it can cost $120,000 to retrofit an existing crane with one of VYCON's kits, the company reports that customers are recouping their investment in 3.5-5 years.
More: Greentech Media
MIT Students Invent Energy-Harvesting Shock Absorber, Plan to Take Over the World
Intel Demos RF Energy Harvesting Technology
Burger King Installing Speed Bumps That Generate Electricity