Resiliency benefits of solar batteries
Last updated 7/6/2021
The primary reason that most people install an energy storage system at their home is for the benefit of resiliency: batteries provide emergency backup power in the event of an outage. Though infrequent in most parts of the country, grid outages do occur, and energy storage allows you to keep the lights on even when the rest of your block has no power.
How do batteries work during outages?
Given how many batteries exist in everyday life, you’re probably very familiar with how batteries operate: they store power for use at a later point in time. During an outage, energy storage continues to operate by creating a miniature “energy island” for your home or business. So even when the rest of your neighborhood is without power, you can pull from your battery to keep your lights on.
It’s like how you can use a power bank to charge your phone if you’re away from an outlet and are running out of juice; instead of plugging into a wall outlet to charge your phone with the grid, you can plug into a tiny, pocket-sized battery to recharge your device. This is effectively what you’re doing when the grid goes down; since pulling electricity from the grid is no longer an option, you’re pulling from your battery instead.
Importantly, the types of batteries you install for your home or business have a limited storage capacity and power; as such, most batteries are unable to backup your entire home. Instead, when you install an energy storage system in your home or business, you’ll be asked to choose which circuits (i.e., outlets, appliances and sections of your home) to back up in the event of an outage on a “critical loads panel.” If you’d like to avoid this step and maintain some additional flexibility to be able to change what parts of your home you backup and when, it’s worth looking into smart electric panels, which can help you maximize the backup power and flexibility of your energy storage system.
What happens to solar panels during an outage?
If you’re thinking of installing solar panels to help prevent electricity outages for your home, there’s something you should know: a solar energy system installed without a battery will not continue to produce electricity during an outage, even during the height of a sunny day. There are two main reasons for this:
First, the output of the solar panels on your roof can vary minute by minute throughout the day. While this doesn’t matter when also connected to the grid, if you were to try to power your home straight from solar panels during an outage without a battery, these slight fluctuations in electricity supply would damage electrical equipment and wiring in your home.
But the primary reason solar panels shut off during an outage is for the safety of utility line workers. During an outage, utilities send repair crews all throughout their service territory to try to restore electrical service as quickly as possible. If solar were still producing electricity during an outage, those panels could feed electricity onto the grid, creating a dangerous situation for transmission workers who expect to be working on de-energized wires. For that reason, solar inverters are constantly checking to see if the grid is up and running and will shut down the solar panels’ production if they can’t detect the grid.
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