An early Tesla Powerwall installation in the UK is featured in the most recent episode of Fully Charged.
According to host Robert Llewellyn's guests on the show, combining solar PV with a Tesla Powerwall home energy storage system enables one to limit electricity demand from the grid to only a few percent per the day (at least on the sunny days).
In the average case explored, the electricity usage for the whole year is expected to be 75-80% from the solar/Powerwall system combo, as there are still periods of cloudiness (and less available solar hours available between November and February) that still the grid need to pitch in.
"A small start to what could be a game changing technological shift. A visit to one of the first Tesla Powerwall installations in the UK."