HOME

Closed System Electrochemical Storage

A variant on the 'ideal' fuel cell solution is a closed loop electrochemical storage system which can store a large amount of energy, but cannot actually generate energy.  Such a scheme occupies the middle ground between a battery and a fuel cell - unlike a battery, the storage of chemical energy is physically separate from the conversion process; but unlike a fuel cell, the system cannot be fed an external fuel stream to generate unlimited power.

One system utilising this principle on a large scale was called 'Regenesys' and was produced by a subsidary of Innogy (UK energy company owned by German company RWE).  This system used a polymer electrolyte similiar to Nafion. Cycle efficiency was around 67% with next generation efficiency expected to be around 70%. Unfortunately the system has now been abandoned by Innogy. RWE indicate that this was a commercially motivated decision. See:
http://www.energie.de/bsznewsletter/dokumente/Utility%20Pulls%20Plug%20on%20Regenesys.pdf
http://www.e4engineering.com/item.asp?id=51308&type=Features&pub=eng

RE-fuel is another closed system electrochemical storage technology. The company claims up to 80% cycle efficiency and is currently marketing short range shuttle vehicles and back up electricity supplies. For more information see RE-fuel.com

For more information on electricity storage see: http://www.electricitystorage.org