Today discussed and even already used storage possibilities: You differentiate in various types of storages, like:

• Thermal energy: heat store
• Chemical energy: accumulator, battery, galvanic cell, redox flow cell, hydrogen storage systems
• Kinetic energy: flywheel
• Potential energy: spring (tech.), pumped storage plant, compressed-air energy storage
• Electrical energy: condenser, inductor (especially superconductive inductors)

The fuel cell is often incorrectly assumed to be a type of energy storage. But it is just an energy converter because the fuel cell uses the stored energy in fuels to generate electrical power. Storage of electrical energy comparable with for instance batteries or pumped storage plants is just possible in a system of electrolyzer, hydrogen storage and for example fuel cell to convert chemical energy into electrical energy.

In addition to this the tem is partly used for container, which absorb no energies but fuels:

• depleted gas reservoirs (crude oil and natural gas)
• aquifer reservoirs for natural gas
• tank (container/storage tank and fuel tank)
• absorption storage

Currently the industry is working and developing on the listed storage systems to find a solution for the storage of electrical energy.