A nanostructure energy storage device comprising: at least a first plurality of conductive nanostructures provided on an electrically insulating surface portion of a substrate; a conduction controlling material embedding each nanostructure in said first plurality of conductive nanostructures; a first electrode connected to each nanostructure in said first plurality of nanostructures; and a second electrode separated from each nanostructure in said first plurality of nanostructures by said conduction controlling material, wherein said first electrode and said second electrode are configured to allow electrical connection of said nanostructure energy storage device to an integrated circuit.