I like flow batteries for large energy storage. If you short one out, you simply close the valves and the electrochemical action stops. Normal batteries once the output is shorted they discharge with disastrous results.
But, there are trade offs and this article does not address them.
Efficiency. How much of the energy that gets out into the battery comes back out.
Storage losses. How much of the energy put in is lost with the battery just sitting there.
How many cycles can the battery operate before significant costs are incurred.
How much on going maintenance does the battery need.
If these parameters do not have a gotcha in them, 50 dollars a kilowatt hour will be a major accelerator to the formation of micro grids and of Enphase’s idea of market based electrical micro grids.
We are not there yet, but we are getting closer and closer to a solar plus battery micro grid world.