A hydraulic compressed air energy storage system includes air and liquid tanks, each of which includes interdependent volumes of liquid and air. Each tank includes dedicated passages through which incoming air may be fed, forcing outflow of liquid, or incoming liquid may be fed, forcing outflow of air. Compressed air tanks are connected to a first group of the air and liquid tanks. The system further includes a pump and a liquid turbine, the liquid turbine being electrically connected to a generator for generating electric power. During charging of the system, liquid is pumped through the first group of air and liquid tanks, and air is expelled from the first group of air and liquid tanks and compressed in the compressed air tanks. During discharging of the system, compressed air is released from the compressed air tanks, and said compressed air pumps liquid through the liquid turbine, thereby generating electricity.

In a hydrogen or helium container and method for containing the gas, a double-walled housing is provided, which defines an inter-space between the inner and the outer walls, the inter-space being filled with a fluid at a higher pressure than the pressure of the hydrogen or helium contained within the inner wall.

In a hydrogen or helium container and method for containing the gas, a double-walled housing is provided, which defines an inter-space between the inner and the outer walls, the inter-space being filled with a fluid at a higher pressure than the pressure of the hydrogen or helium contained within the inner wall.

This invention relates to a containment system for storing liquid hydrogen (3), comprising one or more walls forming a containment space (2). At least one of the one or more walls comprises an inner barrier layer (11), an outer barrier layer (12) and one or more spacer elements (14) disposed between the inner barrier layer (11) and the outer barrier layer (12) to separate the first and second barrier layers (11, 12), thereby creating space for a vacuum layer (13) in between the inner and outer barrier layers (11, 12). The outer barrier layer (12) is made of cryogenic ice having a temperature of below minus 150 C.