In order to enable seasonal electrical energy storage, a hydrogen energy storage was developed. This consists of hydrogen generator, metal hydride hydrogen storage and fuel cell. Hydrogen storage benefits from the separation of converter and storage, improving cost efficiency for long term storage with large storage capacity in respect to storage power.
Picture of the energy storage module with PV on the roof and a large side door for easy access.

Through the separation of storage power and capacity in hydrogen storage with water electrolysis, fuel cell and hydrogen storage tank, price reduction can be reached in respect to the equivalent battery storage due to the lower price of storage tank capacity for hydrogen.
Picture of the SELF building with the energy module on the right side (small silver building).

The hydrogen storage system consists of a metal hydrate cylinder assembly of 10 cylinders, each with a volume of 10 l. The cylinders are able to store 4 kg of hydrogen, or 130 kWh of energy equivalent in respect to the lower heating value of hydrogen.
Picture of the energy module with the control on the left and the hydrogen storage on the right.