California Energy Storage Mandate

Doubtful. There are operational requirements for qualifying storage to ensure that the storage is available to balance the large and growing amounts of intermittent renewables on the grid (particularly all the rooftop PV). I hope Tesla looks at this option closely, but my guess is that their goals for the storage and the California system operator's are quite different and incompatible.

Unless they're utilizing the storage in a grid friendly way.

From what I gather solar is still a very very very small percentage of production in CA. What's the rush? AFAIK Germany is just starting out with their storage initiatives and isn't really pushing too hard. Why rush to push storage before solar hits 30% or so of the peak demand?

If this is just to spur the industry within California I can see that, but they're nowhere near a need for storage, right? 2.7GW of rated solar capacity is nothing. Germany has had more installs than that in a month and they don't seem worried about storage yet.