There's no shortage of electric bikes on the market these days, the trouble is that most of them cost thousands of dollars. By adding an electric boost to your existing bike, the GreenWheel is designed to make electric biking more affordable.
Developed by a group of scientists at MIT, the GreenWheel is a self contained unit that includes the motor and battery, along with a generator that can recharge the battery on those long downhill runs. Running on straight electric power, the GreenWheel delivers about 20 miles of pedal free riding, but you can double this by pedaling along as well.
Still a work in progress, the GreenWheel is expected to be available soon for a few hundred dollars. Ah, the cost of being green!