Ditch the Batteries: Off-Grid Compressed Air Energy Storage • Hacker News Board

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

#221

Post by ChuckMcM » Fri, May 25, 2018, 1:58 AM UTC

cwkoss wrote: post #220

ChuckMcM wrote: post #209

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?)

It would certainly increase the heat capacity of the air.

Compressing air into the data center however would not be a win. During compression the air gets hot. In the system that I was pushing the compressed air tanks were outside in the wind so that they were benefiting from the cooling effects of the same wind that was pumping air into them.

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

#222

Post by jgamman » Fri, May 25, 2018, 2:08 AM UTC

binarymax wrote: post #218

cwkoss wrote: post #217

Earlier quoted context omitted.

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.

and use platinum in the fuel cells. the real-world problems are pretty obvious though - Pt is worth stealing and it's expensive 'cause there aint that much of it so you can't expect to use 100x as much as now and not expect the price to change. FC's are niche. Batteries won.

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

#223

Post by gitgud » Fri, May 25, 2018, 2:13 AM UTC

mrfusion wrote: post #131

throwaway5752 wrote: post #82

Earlier quoted context omitted.

There's a video somewhere of a failing flywheel, it's a fairly energetic explosion. I follow the energy space, also, and ... while I didn't expect Li batteries to have grid scale roles, I didn't think flywheels were going to succeed there. They have properties more like ultracapacitors (discharge rate suitable for continuous backup, clean up messy grid sine waves). I thought pumped air/pumped water was more likely be…

Why can’t we bury flywheels to protect from any explosions?

Well yeah you can bury anything to keep it safe, but at what cost?

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

#224

Post by Neeek » Fri, May 25, 2018, 4:15 AM UTC

josefresco wrote: post #72

davidhyde wrote: post #60

Earlier quoted context omitted.

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.

And then also goes in to detail about small scale iso-thermal setups that have negligible thermal losses. Apparently "author did not mention" actually means "I did not read the article".

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

#225

Post by jhayward » Fri, May 25, 2018, 4:48 AM UTC

ballenf wrote: post #114

dwyerm wrote: post #89

Earlier quoted context omitted.

> it's a fairly energetic explosion So is a lithium battery explosion. So is a gasoline explosion. So is a flour mill explosion. So is a wind turbine explosion. Energy is energy, and losing control of energy is never great, no matter where it comes from. So while I catch your meaning, it might be better to phrase it with respect to how controllable that energy is. From what I know of flywheel storage, the problem mos…

Also flywheels don't give off noxious fumes during failure.

Are you sure? Metal fumes and vaporized epoxies are usually pretty toxic.

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

#226

Post by jhayward » Fri, May 25, 2018, 4:52 AM UTC

joncrane wrote: post #75

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?

As of about 10 years ago our data centers always had 1 out of 4 generators configured with a big M/G flywheel on the output shaft. The flywheel momentum guaranteed generator start, I don't know the latency but it was on the order of a handful of cycles.

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

#227

Post by [deleted] » Fri, May 25, 2018, 6:08 AM UTC

josefresco wrote: post #72

davidhyde wrote: post #60

Earlier quoted context omitted.

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.

[deleted]

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

#228

Post by jacquesm » Fri, May 25, 2018, 7:01 AM UTC

cwkoss wrote: post #219

jacquesm wrote: post #154

Earlier quoted context omitted.

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?

Energy storage in superconducting loops. This is done on a small scale already for ride-through and power stabilization purposes but it is expensive due to the non-room temperature super conducting technology used which requires cooling down the superconductor.

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

#229

Post by gargravarr » Fri, May 25, 2018, 10:28 AM UTC

mschuster91 wrote: post #208

gargravarr wrote: post #180

Earlier quoted context omitted.

Some DCs do, but the need to keep them spinning 24/7/365 is a big maintenance issue, so given the advances in battery tech, I'd assume batteries would supplant flywheels for cost and safety reasons.

> but the need to keep them spinning 24/7/365 is a big maintenance issue So is keeping batteries up to date. Many a failure has been attributed to stuff like: - batteries gone bad without anyone noticing over the years (lack of acid, crystallization, loose contacts, dust in cooling components, ...) - switch-over between grid and battery inverters fails somewhere - some part of the inverters fail when they're idling f…

For the most part, but every few years the bearings will need replacement. This means shutting the entire thing off and dismantling it for several hours. For redundancy, you therefore need multiple flywheels to cover for the maintenance periods.

Batteries can and indeed do go bad without warning, but current sophisticated UPS monitoring systems are able to detect failures, track battery ages and raise alerts (whether anyone actually acts on those alerts or not is another matter...). I've also found that lead-acid batteries last longest as long as there is some amount of power continuously trickling through them - I have an APC UPS at home with its original batteries from 2010, and they still provide ~1h of runtime at 20% load. And with most DC-grade UPSen, batteries can be replaced in situ without powering the device or any connected equipment off.

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

#230

Post by paulmd » Fri, May 25, 2018, 12:55 PM UTC

glenneroo wrote: post #212

paulmd wrote: post #197

Earlier quoted context omitted.

> 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.

We don't need billions of years though, "hundreds of years" of fuel is hopefully long enough for us to figure out the tech that will get us through the next couple hundred years after that. And nuclear is fine for that. We're not talking kicking the can down the road by 20 years, we're talking hundreds or perhaps thousands of years of fuel.

Humans are plenty smart and the people of tomorrow will be better equipped to solve tomorrow's problems.

It's not even a matter of "ripping off a band aid" and paneling up the planet - solar panels aren't going to last hundreds of years either, we will be lucky to get 30 years out of them. Can we make more, sure, but we could also do nuclear and then make solar panels in 500 years when we're running out of fuel.

The biggest problems are that we need to come up with the political will to reprocess waste (extracting additional usable fuel and compacting the amount of true waste that needs to be disposed of) and then dispose of it in a proper repository rather than just letting it sit around on-site indefinitely Fukushima-style.