Burger King uses MotionPower to generate electricity from drive-thru traffic

Now this is just too cool. Making use of the weight of cars while slowing down to generate electricity. There is no free energy so the generating process (as it relies on the weight of the car to drive the generator) costs the car owner some energy (the car has to move up the incline in order to get the weight of the car onto the generator in order to drive down the mechanism). I am glad that they specifically note:

The manufacturer envisions larger MotionPower machines installed in places where traffic is slowing down to prevent the scheme from requiring extra energy input from vehicles.

If the vehicle is in the process of slowing down, the forward energy is being waisted as it is converted to heat by the braking system. By adding these minimal "speed bumps" to the slow-down path, energy that would have been wasted by the breaking system will instead be converted into electricity. The car going up the slight incline of the generator will dissipate forward energy similarly to the braking action while activating the generator. In these cases, this is energy that you are "giving away" anyway so might as well convert it to electricity for general use.

As with most devices in this category, I would like to see the ROI schedule.