Looks like we need a refresh on kW and kW.hrs, The kW is an instantaneous figure and is the rate energy is delivered. The kW.hr is the total energy delivered which means a 10 kW.hr battery can deliver 1kW continuously for 10 hours or 10 kW continuously for 1 hour. This is the elegance of the flow battery, to increase the total energy available you simply increase the size of the storage tanks. The instantaneous kW available will not increase, to do this you add more electrodes in parallel.
So flow batteries not as good as other technologies for surge (i believe some redflow installation also have a small capacity lithium to cater for this) but they should be extremely cost effective for large scale load leveling as will be required in the future. Its a chemical based equivalent to pumped hydro, the bigger the reservoirs the more energy stored. Litre for litre there will multiples of hundreds comparing the flow battery energy stored to even the best situated pumped hydro though.
So I would like to see redflow come out with a system that had storage tanks much larger than those in the current installations, where space is an important factor. Hope this makes it clearer what a larger flow battery may look like. Also remember the big lithium batteries being built at present are being sold by the media as storage batteries and although they store energy, its their surge capacity that is being used as the intermittent nature of wind and solar needs a large surge capacity component in the grid for network stability and to give time for other forms of generation to ramp up. The flow batteries opposition is the pumped hydro, thermal storages, compressed air storages etc etc. Have had a couple of reds and hope this makes sense when I review it tomorrow.!
RFX Price at posting:
2.6¢ Sentiment: Hold Disclosure: Held
(20min delay)