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Ditch the Batteries: Off-Grid Compressed Air Energy Storage

lowtechmagazine.com

211–220 of 238 posts

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

#211

Earlier quoted context omitted.

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

Only some of them have flywheels. The large telco datacenter I visited had huge pallets of batteries to cover the time needed for the diesel generator to start.

Might be more a telco thing as they tend to regard serious outrages as a one every one or two generations as just about acceptable.

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

#212
post #197

Earlier quoted context omitted.

It's kind of bizarre how nuclear had achieved a sort of counterculture renaissance. It has many, many drawbacks too numerous to go into here that are technical and sociological in nature. And anyway, you tried to be too clever. I said "non-renewable" and not "carbon free" just to avoid this conversation. Unless you can start synthesizing utility grade quantities of well-behaved fissile material at a net energy surplu…

> Unless you can start synthesizing utility grade quantities of well-behaved fissile material at a net energy surplus then it's not renewable even if we have decades/centuries of supply. Someday, even the Sun will run out of fuel. In the long run, we are all dead - unless someone figures out how to reverse entropy. http://www.multivax.com/last_question.html

We still have 5 billion years to figure that out. Until then we should probably stick to worrying about energy problems of today.

edit: Love reading that short story, it somehow never gets old.

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

#213
post #199

Earlier quoted context omitted.

It would really be something if that miniature nuclear reactor NASA tested ended up being viable for cars, realizing one of the dreams from the early nuclear age.

Given that even a small reactor still requires considerable shielding, generates waste that could be used for nuclear proliferation (if ammassed), and emits harmful radiation, I would say chances of a nuclear car for the every man are slim to none.

There's that, but on the other hand, small gasoline vapor explosions are quite harmful and require considerable shielding, and generate waste that is destroying our ecosystem.

The nuclear waste problem seems to be not so severe in the age where everything is tracked every second; and it doesn't need to be solved completely - just raise the cost of (illegal) waste extraction to be considerably higher than getting it from alternative sources, and you're set.

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

#214
post #125
post #74

Earlier quoted context omitted.

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.

Not necessarily , 1.3MJ (360 Wh; but screw that unit) of diesel isn't much of an explosive under normal circumstances. It really depends on the maximum power output under normal operation, and whether it can occur uncontrollably.

Energy density and release rate tend to have inverse relations, for a given energy mechanism.

TNT has about 1/10 the energy density of petrol or diesel. Capacitors have lower capacities than batteries.

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

#215
Seems like a technology that has narrow usecases like where cogeneration is possible. I guess large city's and industrial applications which can use the waste products of the thermal cycle.

For alternatives, my money in the long run is on molten salt batteries [1] for large scale. Technology also has benefit of increased industry knowledge of how to utilize molten salts safely which will benefit LFTR research.

(1) http://news.mit.edu/2018/metal-mesh-membrane-rechargeable-ba...

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

#216
post #170

Earlier quoted context omitted.

>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 energy storage technologies to catch up. Flywheel and hydrogen fuel-cell also often come up but I think we're at a point now where batteries are going to take off simply because of their wide area of applicability. With that economy of scale costs…

Don't rule out hydrogen just yet - at least not for cars (and then using your car as a generator to power your home): http://www.thedrive.com/tech/14431/are-hydrogen-cars-the-nex...

I'd be very surprised if hydrogen vehicles work out. Hydrogen is not a source but rather a store of energy like a battery is. There's a few practical and technical issues:

1 it would require building out entirely new infrastructure, running up against severe NIMBYism at this point. It's incredibly hard to even build new power lines right now. Try a highly combustible, very leaky gas.

2 it's far cheaper to just strip H2 from natural gas, which releases carbon (unless you capture it, increasing cost), so not carbon free unless you force using electrolysis from renewable power sources

3 Electrolysis efficiency is ~70%, fuel cell efficiency is ~60%, so round trip efficiency is 4 in vehicles, fuel cells end up charging the battery toi power the motor anyway, so the energy loss from the battery is a wash

The one thing they have is range and speed to refuel, but as batteries get cheaper and better that will be minimized before H2 gets big enough to take over.

There's lots of big companies with smart people who are still pushing for this so hopefully they know what they are doing (mostly in Japan it seems)

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

#217
post #170

Earlier quoted context omitted.

>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 energy storage technologies to catch up. Flywheel and hydrogen fuel-cell also often come up but I think we're at a point now where batteries are going to take off simply because of their wide area of applicability. With that economy of scale costs…

Don't rule out hydrogen just yet - at least not for cars (and then using your car as a generator to power your home): http://www.thedrive.com/tech/14431/are-hydrogen-cars-the-nex...

Have we figured out a good way to store Hydrogen that avoids leakage? I've heard that even thick-walled stainless steel vessels can leak ~1% a day.

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

#218
post #217
post #170

Earlier quoted context omitted.

Don't rule out hydrogen just yet - at least not for cars (and then using your car as a generator to power your home): http://www.thedrive.com/tech/14431/are-hydrogen-cars-the-nex...

Have we figured out a good way to store Hydrogen that avoids leakage? I've heard that even thick-walled stainless steel vessels can leak ~1% a day.

Yeah, you coat the cell interior with platinum. Adds significantly to the cost and complexity of production though.

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

#219

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…

There is still one more possible alternative, if only we can get the physics to work: room temperature super conduction. That - if it ever comes to fruit - is going to cause a whole pile of revolutions and unlike most other ideas that rest upon unobtanium actually has a chance of success.

How would room temperature super conduction be used for energy storage?

Or would it just make all of the other technologies much more efficient?

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

#220

I have argued unsuccessfully in the past that this technique would be an excellent data center strategy. That is especially true if you had your data center near the Columbia river and its near constant winds. Using wind power to compress into high pressure tanks, then when you need extra energy you pull it out and pipe the air expansion pipes through heat exchanges in the data center. That way heat from the data cen…

If the entire contents of the data center were pressurized, would it increase the efficiency of air cooling? (Denser air -> more heat capacity?)
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