How does a home solar energy system work?

Your solar panels produce DC power, which gets converted to AC power. This either happens with a small inverter for each panel, or one larger inverter that does the conversion for all of the panels.

The AC power gets wired into your home electrical panel. If the solar panels are producing more power than you are using then the internal voltage will rise above the voltage of the AC power coming in from the street, and your “net meter” (owned by the power company) will allow the excess energy to flow from your house to the street, and will measure the amount and run the meter backwards, recording a credit for you.

When you are using more energy in your home than your solar panels are producing then the voltage in your house will be very slightly lower than the line voltage and the net meter will let electricity flow into your house and run your meter forward.

Your meter runs forward all night long, of course, but during the day your meter can run forward or backward moment by moment as the sunshine changes and appliances turn on and off. On a sunny day when you are not using your air conditioner the meter probably runs solidly backward all day long. You don’t have to think about it. At the end of the month the power company bills you based on the “net” amount of power you have consumed – The amount you took minus the amount you put back. Some months the net amount is negative because you produced more than you used! The power company won’t pay you, but they will continue to keep track of how much electricity they owe you. When you start using your A/C more you will start to draw on that credit. And perhaps in the winter when the days are shorter and your panels are frequently covered with snow you will finally use up your credits and get back down to owing something again.

The cool thing about this topology is that the net meter doesn’t need to know ANYTHING about what type of alternative energy source you have. It just takes electricity from your house when your house voltage is slightly high, and sells you electricity when your household voltage is low.