A recent patent issued to compressed air energy storage (CAES) company SustainX could provide a significant improvement in grid storage of energy, especially for wind farms and solar power arrays.
Compressed air is one of the preferred methods for storing excess energy from renewable sources during periods of peak production. When there is increased demand, it can then be readily harnessed to provide additional electricity, instead of relying on fossil fuel burning 'peaker plants' or other, less desirable alternatives.
The problem with compressing air comes from thermodynamic effects. "Without heat transfer, a gas will increase in temperature as it is compressed; and as it gets hotter, it tends to resist further compression (i.e., each increment of compression must be performed on a volume of gas that is at higher pressure than if it had not been heated by prior compression)." SustainX has developed technology to provide isothermal compression and expansion which gives their system conversion efficiencies of over 90%. And, of course, better conversion efficiencies mean less energy is wasted.
With this technology, SustainX claims a 7x cost reduction over traditional CAES systems. Additionally, according to the company, "SustainX utilizes above-ground storage in the form of industrial-grade, off-the-shelf gas cylinders, eliminating the siting constraints and permitting concerns associated with classical underground CAES."
via: N A Windpower
