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Forget Better Batteries, Nothing That Exists Or is in Development Can Store Energy as Well, And as Cheaply, as Compressed Air (theconversation.com)
An anonymous reader shares a report: The concept seems simple: you just suck in some air from the atmosphere, compress it using electrically-driven compressors and store the energy in the form of pressurised air. When you need that energy you just let the air out and pass it through a machine that takes the energy from the air and turns an electrical generator. Compressed air energy storage (or CAES), to give it its full name, can involve storing air in steel tanks or in much less expensive containments deep underwater. In some cases, high pressure air can be stored in caverns deep underground, either excavated directly out of hard rock or formed in large salt deposits by so-called "solution mining", where water is pumped in and salty water comes out. Such salt caverns are often used to store natural gas. Compressed air could easily deliver the required scale of storage, but it remains grossly undervalued by policymakers, funding bodies and the energy industry itself. This has stunted the development of the technology and means it is likely that much more expensive and less effective solutions will instead be adopted.
This seems unlikely to replace batteries at the small scale. Even discounting the risks of puncture or leakage in mobile devices like cell phones or computers; the equipment necessary to compress air into containers can likely only be scaled down so far before it loses efficiency.
Plus every air compressor I've ever seen or worked with is pretty loud. Maybe there are ways to reduce the noise; but this ultimately seems like more of a large scale way to store energy produced via solar or wind power than a replacement for traditional batteries.
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Saw a pie chart a day or 2 ago that shows natural gas and coal are about equal now in the US market. And since natural gas is now cheaper than coal to build and run, US use of coal will continue to diminish. That, BTW, is the absolutely best way to replace polluting sources, by replacing them with cheaper things that don't pollute. IOW, don't pass a law against something, pass a law that helps create cheaper but cleaner resources and no, that doesn't mean subsidize something, because that is just the people paying more for something through taxes. No, REALLY make it cheaper - make something that is intrinsically cheaper. That's now natural gas. Hopefully some smart guy will build the 90% efficient solar cell, and these guys will perfect their air compression technique and we'll get 100% clean power.
What's the best way to move from coal to natural gas outside the USA? By fracking the F out of the oceans of natural gas reserves that the USA has, and selling it to the furriners... Its a win-win - they get cheaper electricity and the world gets less CO2 and other nasty shit in the air. Trump just did that by harrassing Angela Merkle, the German prime minister, into canceling her country's gas pipeline to Russia, and instead building liquified natural gas seaports for import of LNG by ships from... the USA. We better get to fracking every square inch if we want to reduce pollution.
Having worked with a lot of air compressors over the years I was suspicious of this as an efficient way to convert energy into a storage medium. After a quick Google I found a blurb on a manufacturer's website that up to 90% of electricity used to run a compressor is converted into heat.
https://www.quincycompressor.com/the-benefits-of-efficient-air-compressors/
I'd imagine that large-scale compressors are more efficient, and there would be some heat capture employed to utilize the energy lost there, but can this really compete?
I worked on a project doing exactly this about 5 years ago. The company, called SustainX, i believe is gone and disbanded. There are probably others too. They basically took a giant marine diesel engine and modified it become an air compressor in storage mode, and an expander in retrieval mode. They had solved some of the technical challenges of doing it in a thermodyanically efficient way. Something about isothermal and adiabatic. I forget the details but they have some elaborate mechanism for *both* the compression and expansion of the gas to extract a lot more usable energy. The big problem was storage. They used a giant tank array for their test system. They really wanted to deploy it globally but it turns out there's only a few locations in the entire word that have suitable geology for underground storage. So since tanks were relatively expensive and the geology wasn't prevalent, the company didn't sell anything and folded. Cool idea and very technically savvy company though.
Scott
Someone proposed putting a large bag of air under lake Ontario and filling that. I can't find the study. Best places are either next to a large city (Toronto), nuclear plant (Pickering or Darlington) or wind generation. The sealed bag meant they could use clean, low humidity air. Not sure how they solved the heat problem (compressing the air makes it hot, if you lose the heat then you lose a high percentage of your energy. Ontario doesn't have the political competence to make this viable though. Maybe it would work on the US East coast?
The answer lies in the phrase "economies of scale." There is almost NOTHING that you can do in your home, and have it be more efficient than the industrial version of the same. From baking bread to energy storage... industry has you beat. Solar power, wind power, battery storage, compressed air storage, geothermal... the list just keeps going... This is why as much as I love solar, I'll probably never have it on my house. The industry will find a way to do it better than I can, and I'm OK with that. Healthcare realized this fact decades ago.
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Except they got promoted. It's pretty much a requirement to win the Presidency, between Iowa's first -in-the-nation caucus and the great corn states' electoral votes.
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