So, ignoring what the twisty turny torquy stuff works against, have a look at the energy involved...

Li-poly batteries have an energy denisity of around 350Wh/L (from PowerStream)

This is 1260000 joules/litre

Looking at two typical pedals with a length of 10 cm, a depth of 2cm, and the battery width of 1cm, then the volume will be 4 x 10 x 2 x 1 = 80cm, this 80/1000 = 0.08l.

This gives us 1260000 x 0.08 = 100800 joules.

Given E = mgh, this re-arranges to h = E/mg (sorry, edit).

g ~ 10 (ie that rounded up 9.81 from school) and mass of bike & rider = 100kg.

So the batteries (100% efficiency all round), would lift you up 100 metres.

So in the real world you would be paying £200 to lift you through ~50m (50% efficiency) around 300 times (recharge cycles of Lithium batteries).

Bargain .....