Originally Posted by AllenG
Energy per volume or weight (there is a term I'm looking for that I can't remember, the engineers will know). Compressed air takes up a lot of room, and to have any range the storage tank is going to be quite large, and therefore heavy. Water powered systems use pressure, same as compressed air, since fluids cannot be compressed they have to use gravity (your bike would be many stories tall) or contained in a closed loop. There the pressure would be added by compressed air, and you would have to have tanks again.
unless you could build a circulatory system for it. I dont know how any of this would be done im just brainstorming lol so I know most of it probably isnt feasible. In some fashion though...the compressed air might possible be created on spot by a mechanism that creates a vaccum similiar to a turbine. A small turbine powered bike should work in this fashion. My thing is that there has to be some way to multiply the wattage generated by these interactions.