I have invented a new renewable energy device. The device is a CYCLICAL GRAVITY SLIDE ENERGY GENERATOR / EXECUTIVE TOY. The device works by a wagon rolling round a track. The track is slanted downwards for the vast majority of the track, then the track slants upwards for the track to join together. So the wagon can roll round the track again. The reason the wagon can roll round the track is that as the wagon rolls downwards the wagon generates electrical energy. Then the momentum of this downwards roll carries the wagon up some of the upwards hill. Then the wagon is pushed the rest of the way due to some of the electricty gerneated by the roll down of the wagon down the track. The track works a bit like a bobsleigh except with the bobsleigh using the momentum of the downward run to be pushed up some of the hill again.
My solution to this problem is a device that allows a wagon or ball to roll down a track generating electricity as the wagon rolls down the track. Although it is a fact that it takes more or an equal amount of electricity to push a wagon up a hill than would be generated by the wagon rolling down hill. Momentum from the wagon rolling down the hill would still be large enough to raise the wagon a fair distance of the hill. So not all energy generated, from the wagon rolling down the hill, would need to be used to push the wagon up the hill. The momentum energy from the wagon rolling down the hill and the energy generated from the wagon rolling down hill should exceed energy to push the wagon up the hill. So this system can produce an electricity  surplus for other purposes. The larger the wagon and track the more energy produced. 

This would only work,
if you have designed a generator that has no drag back effect,
but normal generators must by pushed with more energy, than they
generate in electricity... so this will not work
with normal generators !

Regards, Stefan.

how about using a neo magnetic sphere that rolls down the hill and as soon as it starts to roll up hill it goes into a thick copper pipe to go uphill? from what i understand when a neo magnetic sphere enters into a thick copper pipe it looses weight i think. so wouldn't it be easier for the sphere to go up?

http://my.execpc.com/~rhoadley/magpipes.htm

"Now, what makes the difference in the time it takes to fall through the pipe?
    a.    The distance between the magnet and the inside of the pipe wall.  The closer the magnet is to the inside wall, the slower the magnet will fall.
    b.    The thickness of the wall of the pipe.  The thicker the wall, the slower the magnet will fall."

I saw an idea for a generator that may make this work....? ?It involves a setup where the magnets AND the coils are stationary.? The moving part is a series of windows in a ring of say graphite or bithmuth.? The passing windows distort the magnetic fields simulating a moving field in the coils.? Apparently the ring does not feel the drag that an ordinary rotor/stator configuration would produce.? Would this be helpful?

That would probably be Al Francour's Interference Generator?

 http://www.theverylastpageoftheinternet.com/ElectromagneticDev/AFrancoeur/interference.htm