Imagine a fuel tank that can store fuel at pressure (it can store at pretty high pressure also) without having any component which provides it constant energy e.g. a pump (i.e energy has been previously fed into the system so as to maintain the pressure in the tank regardless of it's fuel quantity). This can be also be used in fuel stations and aircrafts. So, what will be the advantage of this? I think it will make a sort of super/turbo charger.