What Happens To A Solar Power System During A Grid Blackout?
A frequently asked question that we receive about solar is, “Will my system provide electricity during a storm or hurricane if there is a power outage?”
While you might assume that your solar system will still power your lights and electricity when the grid is down, the truth is, it depends on the specific type of system that you own. To shed some light on this important topic, here’s our analysis of what happens with solar when there is a blackout.
Solar Power During Storms, Hurricanes, And Blackouts
The most likely result is that, if and when the grid goes down, the solar array shuts down as well. This is due to a National Electric Code (NEC) which says that the system must shut down rapidly for safety.
NEC was put in place to protect first responders and utility line workers from electric shock in the event of an emergency. If the power source – your photovoltaic solar panels – continued to be energized when the sun was shining, it could generate and send solar electricity into the power grid and potentially electrocute persons working to restore power after a blackout.
So per the NEC code, the inverter is designed to shut down during a blackout or loss of grid power. Without a functioning inverter, not a single electron will flow in to or out of the house.
This is the case with grid-tied solar power installations, which are about 99% of the systems installed in America. However, there are exceptions.
Exception 1: Battery Backup With AC Coupling
AC coupling is a method whereby the energy generated from solar can be stored in a battery and used independently from the grid. Enphase Energy can be used with the addition of an AC coupled inverter to provide an energy storage solution. Not only can this be implemented on new installs, but this can also be done as a retrofit to existing Enphase systems. Enphase is a name you might recognize if you own a solar system that uses microinverters, or the small inverters located at the back of each solar panel.
AC coupling is a relatively new technology, but will become more and more popular in the future as utilities change the way they charge their users for power, like with time of use (TOU) billing tiers being implemented in California and Hawaii. In this scenario an AC coupled solar power system could be programmed to store solar energy when rates are low, using it to power the home when utility rates are at their highest later in the day (a term referred to as ‘peak shaving’ or ‘rate arbitration’).