A solar system equipped with a hybrid inverter and battery is able to take the power being generated by the panels and; 1.use it either directly in the home, 2.charge the battery, 3.or feed the excess power back into the grid for utility company credits ...as long as the grid remains live.
If the grid should go down a hybrid inverter instantly disconnects from the grid, but it remains live and connected to the solar array and battery. The energy from the solar panels can then still be either used directly by the home or to maintain the charge in the battery. A single LG RESU or the competitive Tesla Powerwall can only power about 30 amps and the loads need to be carefully chosen and wired into a separate essential loads panel. The weather, time of year, and the consumers conservation habits will determine how much total power will be available during a prolonged outage, but it should be enough to carry a homes essential functions indefinitely even if the outage is very prolonged. Hurricane Sandy was a major impetus to the rapid development that has taken place in hybrid solar/battery backup systems in just the last few years.
A solar system equipped with a regular inverter and no energy storage must instantly be shut down in the event of a power outage. This is done to prevent backfeeding power from the solar array into the broken grid and causing harm to the linesmen working to repair it. The house would thus have no power from either the grid or the solar system. Unfortunately a lot of folks on the Jersey shore with simple solar systems were not aware of this requirement until after the hurricane and their homes had no power for weeks on end.
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