With all the current and growing excitement around storage and the grid services markets in the developed world, the developing world electrification opportunity for PV/Storage has been a little drowned out of late... 

In the longer term the requirements for storage in parts of south east Asia, sub-Saharan Africa and India will likely dwarf that of developed world grid services. These markets will require storage solutions with durations of 4 to 6 hrs+ at a price point that is very aggressive to really get deployments moving at scale. The optimum battery chemistry/topology is still very much up in the air in these types of deployments, a Lithium chemistry slam dunk (like the current grid services market appears to be) is nowhere near a foregone conclusion.

There was an interesting guest blog written in the spring for Energy Storage News by Aloke Gupta which deserves to see the light of day again... It's written from a flow battery perspective but many of the points are valid even if you assume a technology agnostic viewpoint...