What happens to your solar energy system if the electrical grid shuts down?
What will happen when the electrical grid shuts down? Heavens will not fall! But, certainly the unwise will be punished and the wise will continue to enjoy electricity. How and why does it happen? Owners of private solar generation are normally connected to the grid. The normal practice is not to install any storage batteries. The grid acts as a very large (AC) battery. Your solar system produces power and feeds it to the grid. At the same time your load is connected to the grid and NOT to your inverter. You are charged for the difference between what you consume and what you supply. In other schemes you get paid for the energy you supply according to the scheme in force. Up to this it is all wisdom. We are assuming that the grid will not shut down. But sometimes it does. What happens then?
What happens when the grid fails
The moment the grid fails, people start taking action to repair it. Workmen will immediately start working: climbing poles and gripping wires, etc. What will happen if your solar system keeps feeding power to the grid? The workmen working in the vicinity of your home could receive an electrical shock. To avoid such possibility, your grid tied inverter is designed to isolate itself immediately from the grid lest the workmen are endangered.
Even if the workmen are not in danger, your own inverter and the system feeding it are at risk. All homes and factories were connected to the grid, and represent a few Gigawatt load. If your 5 or 10 kilowatt inverter tries to feed that load, what do you think will happen? Can you imagine a ‘bee humming bird’ tying to carry a dead dinosaur?
But do not despair? How many times in your lifetime has the grid failed? And how long did the failure last? The fact is if you are not sharing with Hercules the burden of holding the sky, you need not worry. The grid managers are always under pressure to rectify and restore immediately. However, if you do not want to live even with a temporary outage, alternate arrangements are available. You have to install some batteries and extra equipment designed to meet such emergencies. The best alternative is a hybrid system.