Compressed Air as a Method of Storing Wind, Solar Energy

(edited)

Some research is under way on compressed air storage in Switzerland. Researchers from ETH and other institutions are collaborating with the company ALACAES to investigate the potential of compressed air storage in caverns of the Swiss Alps.

https://www.swissinfo.ch/eng/sci-tech/energy-in-the-mountains_a-huge-battery-made-of-air/42362400

http://www.prec.ethz.ch/research/energy-storage/elecstor.html

https://alacaes.com/

Edited by Guillaume Albasini
added Alacaes link
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Storing compressed air in mines could work, but those mines are uncommon and inconveniently located.  Like hydro, there's only so much available, and you have to build transmission lines to it. 

Compressed air also has low round-trip efficiency.  When you compress air, it heats up.  Let it sit for a while, and it cools off.  When you release the cooled air, it provides less energy than you spent compressing it.  Air stored in containers would stay warm for a few hours, at best.  I don't know how long it stays warm in caverns.  

Compressed air storage has been around for decades to provide peaking power.  Even at 50% round-trip efficiency, it's cheaper to run base-load plants at night to compress the air and then use the air during peak hours.  Again though, the opportunities for this are limited.  

LightSail had a plan to improve round trip efficiency.  I forget the thermodynamics, but they wanted to extract heat from the air as it was compressed, store the heat separately from the air, and then add it back to the air upon use.  Last I read, they were designing/manufacturing carbon fiber pressurized tanks for other industries, hoping to use that revenue to fund their storage idea.  

There are a few other air storage startups out there, but I'm not familiar with them.  I haven't gotten the impression that this could be more than a niche application, but again, my knowledge is limited.  

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There have been no viable demonstrations of this concept. Several very well funded companies have tried in the last decade.  All of them burned though $100M+ in capital with absolutely no viable results. 

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8 minutes ago, mthebold said:

Storing compressed air in mines could work, but those mines are uncommon and inconveniently located.  Like hydro, there's only so much available, and you have to build transmission lines to it. 

Compressed air also has low round-trip efficiency.  When you compress air, it heats up.  Let it sit for a while, and it cools off.  When you release the cooled air, it provides less energy than you spent compressing it.  Air stored in containers would stay warm for a few hours, at best.  I don't know how long it stays warm in caverns.  

Compressed air storage has been around for decades to provide peaking power.  Even at 50% round-trip efficiency, it's cheaper to run base-load plants at night to compress the air and then use the air during peak hours.  Again though, the opportunities for this are limited.  

LightSail had a plan to improve round trip efficiency.  I forget the thermodynamics, but they wanted to extract heat from the air as it was compressed, store the heat separately from the air, and then add it back to the air upon use.  Last I read, they were designing/manufacturing carbon fiber pressurized tanks for other industries, hoping to use that revenue to fund their storage idea.  

There are a few other air storage startups out there, but I'm not familiar with them.  I haven't gotten the impression that this could be more than a niche application, but again, my knowledge is limited.  

Incredible!  Learned something new today.

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Compressed air is known by its low efficiencies which results from the heat losses in the compression and expansion modes. Advanced-adiabatic CAES combined with thermal energy storage, expects to achieve up to 70% cycle efficiency, due to redaction of the heat losses. 

According to Technical report by University of Warwick,  effective turnaround efficiencies of  >70% are certainly achievable by 2020. Values up to 80% will be achievable before 2030.

 

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https://qz.com/1355672/stacking-concrete-blocks-is-a-surprisingly-efficient-way-to-store-energy/

 

I personally like the concrete block gravity crane system. If it can be optimized further and use recycled gravel/sand from municipal waste/excavation, unused construction materials, etc, it would be such a simple way to store enough power for thousands of homes at a time.

At 80-85% efficiency, and no need for lithium or rare earth metals, I think that this can be scaled up and combined with solar power to store night time charges, or even maintain it as a reservoir for when other energy storage options are depleted.

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38 minutes ago, NatGasDude said:

https://qz.com/1355672/stacking-concrete-blocks-is-a-surprisingly-efficient-way-to-store-energy/

 

I personally like the concrete block gravity crane system. If it can be optimized further and use recycled gravel/sand from municipal waste/excavation, unused construction materials, etc, it would be such a simple way to store enough power for thousands of homes at a time.

At 80-85% efficiency, and no need for lithium or rare earth metals, I think that this can be scaled up and combined with solar power to store night time charges, or even maintain it as a reservoir for when other energy storage options are depleted.

The funny thing is that this project with the concrete block gravity crane system and the other mentioned before with the air compressed in caverns of the Alps have something in common. Both are based in the little city of Biasca (6000 inhabitants) that incidentally is also the home city of the current Swiss foreign affairs minister.

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