The remote community of people living in Yahel, in southern Israel, have just had a modern compressed-air electric power generation system commissioned, generating 250 kW and having a capacity of 1MWh.
The system was developed by underground compressed air storage expert ‘Augwind’, who has materialized tens of projects of this kind using inflatable polymer tanks that are buried at a depth of four meters underground. However, this is the first commercial project to reach such a capacity.
Air reaching a pressure of 40 bars is pumped inside these 13-meter long tanks by means of water circulation on a connected water tank. This is “charging” the system, storing kinetic energy in the form of pressurized air.
When power is needed, compressed air is released from the air storage tanks and goes back to the compression chamber, and then channeled through a turbine that is connected to an electric power generator via a shaft.
The power to pump the water in the charging phase is provided by solar panels, so the whole system relies upon clean energy sources. Although this power goes through multiple transformations which are all inevitably introducing energy losses, the overall ratio of the system is quite good.
According to Augwind, the system has a total efficiency of 80%. Lithium-ion storage has an efficiency of 90%, so this air-compression battery compares really well.
Additionally, it’s purportedly fit for a service life of more than 40 years, whereas Li-ion batteries can’t go beyond 12 years or 4,000 cycles.
These solutions appear ideal for countries with weak and/or sparse electric grid connectivity, and in Israel, many communities live isolated from the central electric power network.
For countries like Israel that enjoy high levels of sunshine, such solutions are economically feasible. Even in places where the Sun isn’t as frequent though, solutions like hydropower or air turbines can be employed instead.