Compressed Air Energy Storage: Difference between revisions

Revision as of 22:05, 31 March 2020

3kW hr of energy storage at 8 bar requires 65 cubic meters of volume - [1]. Low Tech Magazine on Compressed Air Storage.
- This is 510 cubic meters. But air is free.
But - if you use high pressure, you can reduce that volume down to 300 bar simply using a $300, 1800W Scuba compressor. (can this handle methane or hydrogen? )
Scuba compressor on AliExpress - $300 - [2]
80 cu ft tanks cost $200. That is 2 cubic meters. They are rated for 3000 psi. Standard is 200 bar [3]
For DIY - take schedule 80 steel pipe.
510 cubic meters reduced by 200x is 2.5 cubic meters or 90 cu ft
Take 12" Schedule 160 pipe at 2700 psi rating [4].
A 20' stick of this pipe gets us 15 cubic feet. Need 6 of these pipes to provide 3 kWhr of energy. That pipe is over 100 lb/foot!
Would need 3kWhr PV array to generate the pumping power if we assume 16% overall storage efficiency. This storage efficiency is brute force - would need to look for more efficient expanders. But 6 of these are 12000 lb of steel!
Solution: (1) go to slightly lower pressures. (2) Possibly 3D print plastic pipe. (3) Use automotive high pressure tanks. (4) Use more efficient systems - improve from 16% officiency to 50% efficiency or up to 85% using methods discussed in Low Tech Magazine link above
Schedule 80, 8" pipe may be better- [5] - weight of 43 lb/foot. 1/2" wall.
Or Schedule 40 8" pipe - 1000 psi - 30 lbs/ft [6] - $600 in cost per 20 foot stick.

@@ Line 1: / Line 1: @@
 *3kW hr of energy storage at 8 bar requires 65 cubic meters of volume - [https://www.lowtechmagazine.com/2018/05/ditch-the-batteries-off-the-grid-compressed-air-energy-storage.html]. [[Low Tech Magazine on Compressed Air Storage]].
 **This is 510 cubic meters. But air is free.
-*But - if you use high pressure, you can reduce that volume down to 300 bar simply using a $300, 1800W Scuba compressor.
+*But - if you use high pressure, you can reduce that volume down to 300 bar simply using a $300, 1800W Scuba compressor. (can this handle methane or hydrogen? )
 *Scuba compressor on AliExpress - $300 - [https://m.aliexpress.com/item/32815880523.html?src=google&_randl_currency=USD&_randl_shipto=US&src=google&albch=shopping&acnt=494-037-6276&isdl=y&slnk=&plac=&mtctp=&albbt=Google_7_shopping&aff_platform=google&aff_short_key=UneMJZVf&gclsrc=aw.ds&&albagn=888888&albcp=9317063908&albag=94962804715&trgt=297309937645&crea=en32815880523&netw=u&device=m&albpg=297309937645&albpd=en32815880523&gclid=EAIaIQobChMIq_SpqLrF6AIVA1YMCh3CWAAcEAkYASABEgLdMvD_BwE]
 *80 cu ft tanks cost $200. That is 2 cubic meters. They are rated for 3000 psi. Standard is 200 bar [https://www.google.com/search?q=what+is+pressure+is+nside+scuba+tank&oq=what+is+pressure+is+nside+scuba+tank&aqs=chrome..69i57j0l3.9658j0j4&client=ms-android-verizon&sourceid=chrome-mobile&ie=UTF-8]