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Ditch the Batteries: Off-Grid Compressed Air Energy Storage

lowtechmagazine.com

51–60 of 238 posts

Re: Ditch the Batteries: Off-Grid Compressed Air Energy Storage

#51

I'm surprised no one is talking about how scary it is that you are basically making a high powered bomb at your house any time you have one of these. Anyone that has watched Mystbusters understands the incredible destructive power stored in compressed air. I'll stick with batteries, thanks.

You probably keep multiple gallons of gasoline nearby, tho.

Re: Ditch the Batteries: Off-Grid Compressed Air Energy Storage

#52

Earlier quoted context omitted.

The US government looks into this at a national level. Doesn’t look like it went too well though. https://arpa-e.energy.gov/?q=slick-sheet-project/fuel-free-c...

The article focuses on a small-scale approach that has its own challenges but is different from what your document discusses.

Right. I thought it would be interesting to see it there were experimental findings on a large scale. For example put a massive solar array in the US SW. Transport the power across the country and store excess in geologically stable areas. Those storage facilities then act as power plants at night or if there were delays in sunlight.

Re: Ditch the Batteries: Off-Grid Compressed Air Energy Storage

#53
post #3

An added benefit is you could power your air-tools with something like this without having to convert to electrical energy. As a former off-gridder, that's actually a really big plus. Another non conventional way to store energy is using gravity power modules (example: http://www.gravitypower.net/ ) Storing hydrogen from electrolysis via solar panels also sounds interesting. Basically once your batteries are charged…

My knowledge of physics is very basic and practical engineering is zero, but storing hydrogen in compressed tanks always seem very impractical to me. It's the most freaking volatile element in the universe. And atomic hydrogen reacts with pretty much anything. Leakage and corrosion. From my armchair perspective, storying it in chemical bonds (like nature does) makes a lot more sense.

> And atomic hydrogen reacts with pretty much anything.

But we don't store atomic hydrogen; we store molecular hydrogen (H2).

Re: Ditch the Batteries: Off-Grid Compressed Air Energy Storage

#54

Lightsail Energy tried and failed to bring this to market - not sure whether this can ultimately outperform Lithium Ion Batteries, which have all the pressure of the electronics industry behind them.

The charge/discharge efficiency for compressed air is terrible since most of the energy gets wasted as heat. This plus the terrible volumetric energy storage density makes it a nonstarter for most applications.

Re: Ditch the Batteries: Off-Grid Compressed Air Energy Storage

#55

Lightsail Energy tried and failed to bring this to market - not sure whether this can ultimately outperform Lithium Ion Batteries, which have all the pressure of the electronics industry behind them.

I think the survival of this will be from them explicitly not trying to compete with batteries, but rather for a different market.

Re: Ditch the Batteries: Off-Grid Compressed Air Energy Storage

#56

An early design for the automobile ran on compressed (liquid!) air. http://www.didik.com/ev_hist.htm It might work for some applications, but in 120 years we haven't been able to make it work for cars, at least.

I suggest anyone interested in the history of compressed air storage to also check out http://www.douglas-self.com/MUSEUM/LOCOLOCO/airloco/airloco....

There's also a few articles on the website about compressed air cars and city-wide infrastructure

Re: Ditch the Batteries: Off-Grid Compressed Air Energy Storage

#57
post #48
post #8

Earlier quoted context omitted.

I feel like they have different applications so they're not necessarily competing. Obviously compressed air systems will never have the energy density of a battery, but they could be much more reliable. It also scales up really easily, and I think that's where the sweet spot is - I've heard of people sealing off caves to make giant air storage tanks for these projects.

"sealing off caves" - would love to see, or hear the facts. Specifically, about safety of the pressure "chamber".

https://caes.pnnl.gov/ - it's an interesting project. Apparently it's more like 'underground caverns' than caves.

Re: Ditch the Batteries: Off-Grid Compressed Air Energy Storage

#58

I was quite excited by compressed air storage when Lightsail came into the picture almost 5-7 years ago. Sadly, they could not make the economics work and ended up pivoting into a company that sells carbon fibre tanks for high-pressure storage. As someone who follows the energy space closely, Lithium ion batteries now have so much momentum and $$$ pumped into them via R&D work, it's going to be hard for competing ene…

My concern with batteries is we're so gung ho on producing these, we haven't stopped to consider the environmental impact from the manufacturing process or the incredible task of recycling these once they've outlived their usefulness. It reminds me a lot of when people pushed plastic for everything in order to save the trees and reduce paper consumption. Some 40 years later, we're now trying to get off plastic and de…

Back in the late 1800s, city planners met to try to come up with some plan for dealing with "the manure problem". Large cities couldn't handle the amount of manure produced by the horses in the city. They ended the meeting early, because they couldn't come up with any sort of plan.

Then cars came along and they were all like "Yay! The pollution problem is solved!"

I too wonder what the impact of so many lithium batteries is going to be. I mean, I know they are saying that they are extremely recyclable, and I hope that's true. But I wonder what the unintended consequences of this switch is going to be.

Re: Ditch the Batteries: Off-Grid Compressed Air Energy Storage

#59
post #51

I'm surprised no one is talking about how scary it is that you are basically making a high powered bomb at your house any time you have one of these. Anyone that has watched Mystbusters understands the incredible destructive power stored in compressed air. I'll stick with batteries, thanks.

You probably keep multiple gallons of gasoline nearby, tho.

Not to mention the giant propane tanks that many houses in rural areas already have

Re: Ditch the Batteries: Off-Grid Compressed Air Energy Storage

#60

When compressing air, a lot of heat is generated, and in most cases wasted. When the air is released, it cools down, and has to take heat from the surroundings. Which doesn't work very fast without additional heat exchangers, and especially not in cold environments. Compressed air storage is only efficient with additional heat storage, which is something that promoters of compressed air storage often "forget" to tell…

They didn't forget - it's addressed in detail. They are advocating "small scale" The low efficiency is mainly since air heats up during compression. This waste heat, which holds a large share of the energy input, is dumped into the atmosphere. A related problem is that air cools down when it is decompressed, lowering electricity production and possibly freezing the water vapour in the air. To avoid this, large-scale…

Going "small scale" does not solve the heat problem unfortunately. If it does then the authors did not mention it. All they mentioned is how large scale plants deal with the problem.
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