Inhibiting the champagne effect in hydrostatically compensated CAES systems

A hydrostatically compensated compressed air energy storage system including a dilution system configured to inhibit champagne effect conditions within a compensation liquid, the system comprising:

• a) an accumulator disposed underground and comprising an accumulator interior configured to contain a layer of compressed air above a layer of compensation liquid;
• b) a compressor and expander subsystem in fluid communication with the accumulator interior via an air flow path and configured to selectably convey compressed air into the accumulator at a storage pressure and to extract air from the accumulator;
• c) a compensation liquid reservoir spaced apart from the accumulator and in fluid communication with the layer of compensation liquid within the accumulator via a compensation liquid flow path whereby compensation liquid is displaced from the layer of compensation liquid when the compressed air is conveyed into the layer of compressed air when the system is in use, wherein the compensation liquid flow path includes a compensation conduit extending between a lower end in communication with the accumulator interior and an upper end in communication with the compensation liquid reservoir;
• and
• d) a dilution system comprising a source of a dilution liquid and a dilution flow path in fluid communication with the accumulator interior and configured to supply a flow of the dilution liquid into the layer of compensation liquid when the system is in use thereby reducing an average dissolved gas concentration in the layer of compensation liquid within the accumulator,
• wherein the dilution flow path includes a dilution conduit separate from the compensation conduit.