Talk:Compressed-air energy storage

message: The problem with your article on isothermal air compression is that it deals only in academics, not the day-to-day use of compressed air systems.  
Perhaps the greatest advantage of pneumatics is their safety: moving cutters can be safely cleared no other way.  Material moved through pneumatic (pressure-vacuum) systems clear debris from shops so that fall accidents are far less likely.  Air tools can be safely used in wet environments and explosive atmospheres where electric tools are out of the question.  Air-powered vacuums can easily remove even the most dangerous radioactive materials and asbestos without the dangers of contamination seen with electrical power.  Air agitated paint tanks give the finest finish ever seen.  And the list goes on.
The physics of compressed air use are by definition, appealing: I can think of no less efficient way to deliver power.  But we use air tools constantly, particularly indexing lifts, jacks, nailers, scalers, and air-motor driven tools.  Because rotary screw compressors are now on-par with diesel powered equipment in deep-shaft mines, using the exhaust for breathing air and to cool the hot environment is a real advantage.
Why didn't anyone else think to mention that?  —Preceding unsigned comment added by 209.244.31.59 (talk) 21:05, 17 April 2008 (UTC)
replies: text: This article is about compressed-air energy storage, not use.--Dwane E Anderson (talk) 01:28, 26 January 2009 (UTC)

text: Isothermal compression and expansion represent an ideal case where exactly the same amount of heat is released to the environment as must be reintroduced into the system during expansion. In practice the compressor and air tank will heat up during compression and the engine and tank will cool down during expansion unless very large heat exchangers are fitted or the system is very small or the power level is very small. In the ideal case no energy is lost, but in practice there is the loss of friction and losses to due with not being able to use exactly the isothermal cycle. It would be good to have some real measurements for the article. --Theosch 14:14, 22 March 2007 (UTC)
replies: text: I suppose my confusion arises from my assumption that reversibility=efficiency, whhich does not apply to a system that in one cycle does no work. Either way, an adiabatic compression and expansion cycle also does no net work, and stores much more energy. I agree that an isothermal process probably bears a closer resemblance to the likely cycle of this process. Greglocock 01:36, 23 March 2007 (UTC)

text: I think its ok now. Clarified both the scientific and layman understandings, and, it seems to me, that the large storage (at least if not used in its entirety, but only once filled, used during fluctuations or small cycles of emptying and refilling)  is something near BOTH a reversible isothermal process and an isentropic (=reversible adiabatic) process. פשוט pashute ♫ (talk) 04:37, 16 March 2012 (UTC)
thread_title: Discussion

message: :I think its ok now. Clarified both the scientific and layman understandings, and, it seems to me, that the large storage (at least if not used in its entirety, but only once filled, used during fluctuations or small cycles of emptying and refilling)  is something near BOTH a reversible isothermal process and an isentropic (=reversible adiabatic) process. פשוט pashute ♫ (talk) 04:37, 16 March 2012 (UTC)
thread_title:  OK now? 

message: The calculations are helpful, but impossible to understand with undefined variables. What are P_A and P_B? The article needs to be self-contained or contain references where terms are defined.  —Preceding unsigned comment added by 68.7.105.15 (talk • contribs) 03:12, 27 December 2007 (UTC)
replies: text: The notation should be clear for anyone who has completed a basic college course in thermodynamics; it is assumed that the reader has at least this level of prior knowledge.  See the articles on ideal gas law and Boyle's law, referenced in the section.  (You did read these supplemental articles, did you not?)  The equations illustrate a simple, linear relationship between pressure and volume in an ideal gas under constant temperature conditions.  PA is the pressure at state "A" and PB is the pressure at state "B", corresponding to volumes VA and VB, respectively.  —QuicksilverT @ 06:13, 6 February 2008 (UTC)
replies: text: I sort  of agree, but on balance it is probably a reasonable whinge. I'll see if the other pages have a neat table I can steal.Greg Locock (talk) 06:47, 6 February 2008 (UTC)
replies: text: Balance done. I think now the whole article is comprehensible. Ok now? פשוט pashute ♫ (talk) 05:17, 16 March 2012 (UTC)
thread_title:  Undefined variables 

message: This article talks mostly about the feasibility of compressed air cars. I'd love to see some discussion and math about using compressed air as a large-scale means to store energy. For example, storing the energy created by solar power during the day for use at night. --Gadlen (talk) 23:23, 18 January 2008 (UTC)
replies: text: done a long time ago, and now clarified. פשוט pashute ♫ (talk) 05:17, 16 March 2012 (UTC)
thread_title:  Talk about pressurized caverns 

message: Hey Greglock, this is happytrombonist16, the alter-ego of whatever ip address my computer was using when I posted the facts tag.  I'm kinda new, so it's very possible that wasn't the right tag to use for that situation.  However, it looks like you've fixed most of the things I had a problem with, so thanks!
Happytrombonist16 (talk) 05:32, 27 January 2008 (UTC)
replies: text: Agree. Thanks from me too! פשוט pashute ♫ (talk) 06:37, 16 March 2012 (UTC)
thread_title:  Thanks for fixing things Greglock 

message: At the moment air engine redirects to this page. There exists an article with the much better name Compressed air engine‎. Why don't we move the air engine stuff there, and leave the physics and storage side here? Greg Locock (talk) 09:45, 7 February 2008 (UTC)
replies: text: Now its ok. Redirects to Pneumatic Motor - and here there's an expansion leading to there. (And external link there, to here). פשוט pashute ♫ (talk) 06:37, 16 March 2012 (UTC)
thread_title:  Compressed air engine‎ 

message: The original focus of this article was on the use of compressed air energy storage for utility level power generation or grid energy storage. In my opinion the current version of this article focuses too much on the use of compressed air to power vehicles and not on power generation. Details like power output and storage time for the Mclntosh and Huntofr hybrid plants are missing.
The section on types of compressed storage is inadequate and depends too much on the "German AACAES project information" which understates the efficiency of the hybrid CAES plants. The hybrid plants use the stored cooled compressed air to directly feed air into a gas turbine. This replaces the compressor that is powered directly by a normal gas turbine.  The efficiency of a hybrid plant should be calculated by comparing the energy required to compress the stored air versus the energy required to run the compressor inline with the expansion turbine. See http://www.eere.energy.gov/de/compressed_air.html for details.  —Preceding unsigned comment added by 68.2.181.124 (talk) 21:26, 27 March 2008 (UTC)
replies: text: Apart from the above, this article is at present a mess with much duplication. I'll try to have a go later. Also there is a confusion of many articles all having to do in some way with this subject but inadequately linked. --Theosch (talk) 14:08, 4 April 2008 (UTC)
replies: text: Fixed by now. פשוט pashute ♫ (talk) 06:37, 16 March 2012 (UTC)
thread_title:  CAES article is inadequate 

message: While tidying the "Types" section I removed the following unreferenced text: "see CHARLES HODGES AND THE PORTER COMPOUND AIR LOCOMOTIVES".  If anyone knows what this relates to and can add a ref please do so. Cheers -- Timberframe (talk) 10:52, 21 April 2009 (UTC)
thread_title:  CHARLES HODGES AND THE PORTER COMPOUND AIR LOCOMOTIVES 

message: A similar proposal to the caisson method is being funded by EON - http://www.claverton-energy.com/eon-funding-for-submerged-compressed-air-energy-storage-caes.html The reference quotes the energy content at a depth of about 1,970 feet,as some 6,945 MWh of energy for every cubic meter, however this is clearly wrong, since 1 cubic meter of air at that depth (600 meters) would contain 600m*gravity*1000kg/m^3 = 600*9.8*1000/(3600*1000000) = 0.0016 MWh  
bear in mind, it is not the energy content of the air you are interested in.  It is the energy contect of the 1 m3 of water than you have raised by 1 meter - this contains about 10 times the energy of the compressed air per se.
Are you suggesting that in an adiabatic process there would be any difference in the energy stored, whichever way you calculate it? Greglocock (talk) 02:40, 2 May 2009 (UTC)
thread_title: dispute over energy content

message: Hi, 
I don't understand the formulas. The article says Energy W is a volume integral from V_A to V_B. But the volume of the vessel is constant all the time, may V means the amount of air at atmospheric pressure?
91.8.113.69 (talk) 21:56, 28 November 2010 (UTC)
replies: text: I hope its clear now פשוט pashute ♫ (talk) 06:37, 16 March 2012 (UTC)
thread_title:  Isothermal storage physics 

message: Compressed Air Energy Storage is a very specific term, applying to a particular approach to large scale energy storage within the utility industry. It's relatively simple. But the article as written dives right into all the talk about adiabatic, isothermal, etc. without first explaining the basis of how CAES projects (and there are currently two specific CAES projects operating) work. These more obscure engineering references might be discussed much further down, in the context of some of the R&D going on for CAES.  — Preceding unsigned comment added by Onefinity (talk • contribs) 08:13, 5 January 2011 (UTC)
replies: text: It wasn't really academic, just not written clearly, with different versions put together. פשוט pashute ♫ (talk) 06:37, 16 March 2012 (UTC)
thread_title:  way too academic 

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replies: text: Seems bot gave it a kick. Maybe I'll get the time to fix this. פשוט pashute ♫ (talk) 06:37, 16 March 2012 (UTC)
thread_title: File:Minebw.jpg Nominated for speedy Deletion

message: I am looking to different energy storage process, and I think a french version of you article will be welcome, how can I proceed ahead ?  — Preceding unsigned comment added by Mbariou (talk • contribs) 10:33, 7 November 2011 (UTC)
replies: text: IMHO, open an article in French, and make it a stub, and in the talk page suggest it be translated from English. פשוט pashute ♫ (talk) 06:37, 16 March 2012 (UTC)
thread_title:  I suggest to translate this article in French language 

message: I added some material to the history section with cites in response to the expand section tag placed there.  After making the additions, I removed the tag.  If anyone feels further expansion is needed, feel free to restore it.  There certainly have been many more announced projects and these were not mentioned.  J JMesserly (talk) 17:45, 14 April 2012 (UTC)
thread_title:  History: expansion needed tag removed 

message: Note on a retracted bit of info regarding salt dome capacities.  In the Times article I cited, Wald wrote that the salt cavern could handle 5 times the 1100 psi pressure that McIntosh now uses.  Others may see this and want to mention it as I did.  I wound up retracting it because of an authoritative report in Gas Turbine World, Sept-Oct 2009, editor de Biasing states that the max allowable pressure is calculated at .9 of depth.  So the ceiling of the McIntosh cavern at 1500 foot depth allows a max of only 1350psi.  a reprint may be found at www.espcinc.com/library/GTW%20 ACAES%20Article.pdf. I suspect Wald is in error, but I don't know.   Since it is contested, I pulled it.  -J JMesserly (talk) 10:30, 17 April 2012 (UTC)
thread_title:  Contested NYTIMES statement 

message: I wonder why there is no mention of a trombe as a means of storing compressed air.  — Preceding unsigned comment added by 83.240.200.90 (talk) 18:15, 3 December 2012 (UTC)
thread_title:  Trombe 

message: Please see http://www.lightsail.com/tech.html and their CEO's Google Solve for X talk from a few days ago for the details, but I'm not sure which category (e.g. hybrid etc.) this fits into. so could someone please add it to the article? Apparently using water mist as a heat exchanger is a completely new idea bringing efficiency from 30% to 70%, and LightSail has patents on it. I'd feel more comfortable if an expert took a look at it before it was added. Neo Poz (talk) 23:15, 12 February 2013 (UTC)
thread_title:  LightSail.com claims 70% round trip power efficiency using water mist cooling 

message: Rheinisch-Westfälisches Elektrizitätswerk AG is developing 2 new systems; see
ALACAES and ADELE.
Ref 2: http://content.lib.utah.edu/utils/getfile/collection/etd2/id/86/filename/1430.pdf
Mention in article
KVDP (talk) 17:36, 24 July 2013 (UTC)
thread_title:  RWE 

message: This article should talk about the economics of CAES, e.g. how it compares to other energy storage technologies, and the levelised cost of energy when used with energy generators.  — Preceding unsigned comment added by 101.191.212.184 (talk) 07:03, 22 October 2016 (UTC)
thread_title:  Economics 

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message: The entry in the "History" section for the power plant in McIntosh, Alabama contains the words "Although the compression phase is approximately 82% efficient, the expansion phase requires the combustion of natural gas at one-third the rate of a gas turbine producing the same amount of electricity at 54% efficiency". I'm confused; is this some sort of hybrid system that combines a gas turbine with CAES? Or is the heat needed to provide energy to help the gas expansion? Whatever it might be, the article should make this clearer, and explain exactly how it works. — The Anome (talk) 07:33, 15 May 2024 (UTC)
replies: text: From your description it's basically a supercharged gas turbine, using the high pressure air sourced from the storage rather than a conventional supercharger. Greglocock (talk) 22:05, 15 May 2024 (UTC)
thread_title:  McIntosh, Alabama: "requires the combustion of natural gas"?