Adding battery backup to a solar array is costly, but neccessary for a grid tied island situation. Without battery backup a solar system must shut down instantly anytime the grid fails. This is done to prevent back feeding into the grid as the linesmen are wroking on it.
Most of the newer battery backups have built in mechanisms that will instantly disconnect the home from the grid (called co-incidently, "islanding") and divert the solar power to the battery. For a mainland application the best solution currently is likely the
SolarEdge EnergyHub system but it has one serious shortfall for island application, there is no AGS, automated genertor Start/Stop. If the grid is out for any length of time during a January blizzard there will be no power to charge the battery until the sun again comes out and the modules slide their snow. The system will automatically restart then but it might be too late.
There are however two excellent inverter systems that have AGS; the
Outback Radian and
SolArk. They were both originally designed for total off-grid installations but also work extremely well when grid tied. If there were again a prolonged outage during a blizzard the inverter would draw the power of the batteries down to a pre-set level, and then start the generator and run it long enough to re-charge the batteries. As long as there is fuel in the generator the house will never be without power ...and it will mostly be powered freely by the sun