A landmark report from Clean Power Research for IREC proposes a methodology for the value of solar PV+energy storage that could be used in any location.
customer sited storage 
Valuing Customer-Sited Solar and Storage: is adding batteries worth it?
The concept of adding batteries alongside a utility customer’s solar array intrigues utility customers, solar developers and utility planners on several levels, but the underlying question for everyone is whether adding batteries is “worth it.”
