2015-01-26 17:01:45 -0600
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Great question - it's one that a lot of people ask. For the safety of emergency responders and electricity utility repair-people, grid-connected solar systems are required to stop sending power into the grid as soon as the grid goes down.
More specifically, if there is a blackout, your solar system's inverter (or microinverters, if you have them) will automatically stop your solar panels from putting power into the grid. This is called 'anti-islanding' protection: Islanding is the phenomenon where your grid-connected solar panel system (or wind turbine, diesel generator, etc) continues to produce power during a blackout. It is dangerous for anyone working on the power lines, who anticipate that there is no electricity coursing through the wires. This is why all inverters for grid-connected systems are required to have anti-islanding protection. Your situation would be no exception. This generally means that you cannot use the electricity produced by your solar panels when the grid is down.
That being said, there are some inverters that will allow you use a battery backup or your solar panels in the event of a blackout. They will do this by either:
1) completely isolating your home from the grid - thus eliminating the 'flowback' of electricity to the grid while still enabling you to use the power in your home as you usually would; or
2) allowing you to plug the devices you want to use directly into a special outlet in the inverter - if you have this kind of inverter you won't be able to use everything in your house, but you will be able to run some essential appliances.
Hope this helps!