As energy has a usefulness and intrinsic value that even gold lacks. It could be traded anonymously like cash like batteries as dollars or as energy storage and quick and efficient transfers becomes smaller and more convenient. Im thinking specifically electrical energy with batteries and capacitors but even gas could be used.
It could be created by individuals with solar panels or bike mounted generators. It could be stored as potential energy in large amounts as heat or pressure and then converted back to electrical energy when needed. It could be networked for large transfers. There could even be large banks that hold energy as a business, but they would not be able to lend more than they hold. Private individual energy storage would be the most secure from government or other seizure obviously.
Wheres the flaw?
Pocket full of batteries to pay for bread.
Or you are talking about starting your own power plant.
These storage devices you talk about are honestly huge capacitors. Very... Very expensive.
If we tap into the magnetic field we live in to operate our electronics, the energy storage model you propose would be moot.