I had a neat idea that just occured to me while trying to go to sleep.
Use a Super cooled Super-conducting ring for a power storage device.
This is already done but keeping the ring cool is a problem.
-First make a ring of superconducting material and place it inside a
container that has solid state magnets all around.
-Fill the container with a coolant enough to drop the SC-ring down to
a SC temperature.
-The ring is now floating inside the container because it reflects all
the magnetic fields.
-Evacuate the container so there is nothing but vacume inside.
-The Vacume won't conduct heat and the ring won't heat up
-It will remain Super-conductiong and energy can be put into it and
retreived from it by induction.