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Ditch the Batteries: Off-Grid Compressed Air Energy Storage

lowtechmagazine.com

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

#71

Post by jandrese »

newman8r wrote: 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…

Some Amish communities have a cottage industry around air powered appliances because the rules state that you can't use electricity for frivolous uses, but people still want a blender or mixer or something.

In practice I think that adding the fittings and the long hose from the tank to your work area probably makes this somewhat impractical, but it's a cute idea.

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

#72

Post by josefresco »

davidhyde wrote: post #60
josefresco wrote: post #32

Earlier quoted context omitted.

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.

Come on dude...

Small-scale compressed air energy storage systems with high air pressures turn the inefficiency of compression and expansion into an advantage. While large-scale AA-CAES aims to recover the heat of compression with the aim of maximizing electricity production, these small-scale systems take advantage of the temperature differences to allow trigeneration of electrical, heating and cooling power.

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

#73

Post by JohnJamesRambo »

beat wrote: post #51
JohnJamesRambo wrote: post #44

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.

Gasoline has to be mixed in a perfect ratio with air to be dangerous and explode. A simple leak from that enormous amount of air storage could be catastrophic. A leak of your gas tank and it just piddles out on the ground.

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

#74

Post by ajuc »

jandrese wrote: post #62
mabbo wrote: post #31

> However, to store 360 Wh of potential electrical energy, the system requires a storage reservoir of 18 m3, the size of a small room measuring 3x3x2 metres. The authors note that “although the tank size appears very large, it still makes sense for applications in rural areas”. This would light a home for an hour, with LED bulbs and careful usage. And all it requires is a room-sized storage tank. So if I wanted somet…

For home use you also have to consider that you're basically making a bomb every time you store energy in the thing.

Any kind of high-density energy storage is basically a bomb.

If you charge or discharge Lithium polymer or lithuium ion batteries "wrong" they explode too.

I wouldn't want to be near a flywheel that stores 360 Wh of energy when it breaks.

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

#75

Post by joncrane »

drizzle87 wrote: post #24

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…

Aren't flywheels used in datacenters to cover the split second between when the power goes out and the generators kick on?

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

#76

Post by JoeAltmaier »

evan_ wrote: post #59
beat wrote: post #51

Earlier quoted context omitted.

You probably keep multiple gallons of gasoline nearby, tho.

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

Not the same? Shoot a propane tank, it leaks. No oxygen in the tank.

There is very little outside compressed gas that can explode disastrously without oxygen. A tank of compressed gas is probably high up on the 'bomb in the house' category. Just under the water heater I suppose.

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

#78

Post by dsfyu404ed »

JohnJamesRambo wrote: post #44

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.

Physics is physics matter how you cut it.

A compressed air tank is arguably less of a bomb than the battery under your feet in a Tesla and the cleanup is much better.

Compressed air tank failures do not result in instant fire. Most failures take the form of leaks. Catastrophic failures of properly designed pressure vessels operating at their intended pressure are basically nonexistent because a damaged pressure vessel will usually fail by leaking at the point of damage.

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

#79

Post by dpcx »

Joey Hess has been using his fridge for off-grid energy storage... With lots of data around what he's seeing. It's really interesting, and he still gets to keep his food cold.

EDIT: Not really used as a battery, but probably could be.

http://joeyh.name/blog/entry/fridge_0.1/

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

#80

Post by al2o3cr »

drizzle87 wrote: post #24

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…

I suspect large-scale fixed installations are more likely to end up using some kind of flow battery:

https://spectrum.ieee.org/green-tech/fuel-cells/its-big-and-...

The big advantage there is independent scaling: peak discharge is tied to the total membrane area / pumping capability while capacity is tied to the amount of reactants that can be stored.

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