Battery Systems
- Saltwater
- lithium ion
- forklift and golfcart battery
Kenetic Energy
- flywheel
- hydro storage
Thermal
- hotwater tank
Chemical
- hydrogen
- methane – biogas above/underground resovior for storing methane.
https://www.genstattu.com/catalogsearch/result/?q=16000 i have seen batteries like this combined for aircrafts if you need portable power.
https://www.youtube.com/watch?v=ZyfXvFicp8M free power from powerlines
