Storing Wind Power Energy in Compressed Air Tanks Could Change the World
Photo: Flickr, CC
Capturing the Wind for Later Use, More or Less...As we've said many times in the past, wind power is great, but to use it to its fullest potential, we need to figure out how to cheaply store the energy that it produces at times when we don't need it (meaning mostly at night). Various schemes have been been proposed to do this, including using batteries from hybrid and electric cars - either at the end of the car's life or with vehicle-to-grid (V2G) connections - and pumping water uphill or holding it in huge reservoirs behind hydropower dams. But we don't yet have that many EVs, and some places don't have much hydro, which is why compressed air storage seems interesting right now.
One company working on this is SustainX:
In conventional compressed-air storage, electricity is used to compress air, which is stored in underground caverns or aquifers. That air is then released to drive a turbine-generator to produce electricity when needed. Such storage costs roughly a tenth of what battery storage costs, but it isn't used much because in large part because it requires a location with underground storage space. SustainX's system eliminates this problem because it can efficiently use above-ground storage tanks rather than caverns. [...]
The company reduces costs by using pistons, rather than turbines, to generate electricity. Gas turbines can only generate electricity from a narrow range of air pressures. The pistons can operate at a larger range--and because air can be compressed more, the system can store more energy. What's more, the pistons operate well after the pressure in the tank has fallen too low to drive a turbine.(source)
So basically, SustainX's secret is cost reduction. The general principle of compressing air to later use it to generate electricity is hard to improve upon, but tweaking the tanks and generators to make them less expensive could help bring costs down to a level where it makes sense to deploy this technology on a large scale (probably in areas where electricity is most expensive at first).
SustainX has raised $20 million in venture capital to make this happen. We wish them the best of luck, because we really need this type of technology if intermittent sources of clean energy are to become bigger players in the world energy market.
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