[jumper]

I doesn't matter how much power it generates, what matters is how economically it does so. Add in wear and tear costs in the form of maintenance salaries and new parts, and pretty much anything like this becomes worse than useless very quickly, and that's ignoring the initial costs to manufacture\install and the extra effort people expend to open it! And, eh, you know, I'll let everybody else tear apart their insane power production claims, but, "Each time you pass through the door you generate enough power to make a cup of coffee." Yeah, and I've got a bridge to sell you. ;)

[flashgordon]

well you are right.. but wear-and-tear is there whether you are harnessing the power or not. it is a sunk cost... it is essentially a matter trapping a bit of that energy...

ok wear-and-tear of the motor is a different issue - perhaps an opportunity for innovation to increase efficiency and decrease W and T?