274. FLOW BATTERIES

Flow batteries are a game-changing development which I learned about from Jim Fraser over at the Energy Blog -- the best energy R&D blog on the web. From Jim's article:

Flow batteries are emerging energy storage devices that can serve many purposes in energy delivery systems. They can respond within milliseconds and deliver power for hours. They operate much like a conventional battery, storing and releasing energy through a reversible electrochemical reaction with an almost limitless number of charging and discharging cycles. They differ from a conventional battery in two ways 1) the reaction occurs between two electrolytes, rather than between an electrolyte and an electrode and 2) they store the two electrolytes external to the battery and the electrolytes are circulated through the cell stack as required. The great advantage that this system provides is the almost unlimited electrical storage capacity (MWh), the limitation being only the capacity of the electrolyte storage reservoirs.

This is a new technique for storing large amounts of power which can be used in a distributed fashion (i.e. in individual buildings or facilities), or as a large scale substitute for pumped storage or CAES (compressed air energy storage). The only limitation on the amount of power the batteries can store is the size of the tanks storing the electrolytes. This is another technology which promises to make intermittent sources like wind and solar much more practical. I'll refer you to Jim's excellent explanation for the details.

-- by JD