What I have gathered in from this Jupiter Power Study is they are looking to see if they can make money by selling electricity services like frequency stabalization, voltage regulation and/or uninteruptable electricity.  This along with plain old lease the batteries. 

When the batteries come back in from lease, they are looking at repurposing in a ESS unit.  I think this is what TESLA is doing or were doing.

The question is can they make any money doing this???