Battery Energy Storage System

How do solar batteries work?

Battery storage systems or battery back-up work by keeping energy produced by your solar panels for later use instead of sending it back to the grid.  The higher your battery's capacity, the more solar energy it can store.

If your solar panels are producing more electricity than you need, the excess energy goes towards charging the battery. Later, when your solar panels aren’t producing electricity, you can draw down the energy you stored earlier in your battery for day or night use. You’ll only send electricity back to the grid when your battery is fully charged, and you’ll only draw electricity from the grid when your battery is depleted.

Reasons why you should consider battery back-up for your home

  • Energy storage is especially important for electric vehicles (EVs). As a current or future electric vehicle owner, it might be beneficial for you as Evs increase electricity demand at peak times when you come home from work and plug in your car for a nightly recharge.

  • Another reason to consider storage when going solar is the level of energy resiliency you can achieve from a solar plus storage system. When the electric grid goes down due to technical errors or extreme weather events, solar panels plus energy storage provide resiliency by ensuring you have electricity at your property even when the grid can’t provide power.

  • As a taxpayer you are eligible for 26% investment tax credit (ITC). Although you should always keep in mind that the battery itself isn’t considered renewable energy, because it can also be charged by grid electricity. In order to get the tax credit benefits, your battery needs to be charged by renewable energy.

  • Self-generation incentive program (SGIP). Available to electric and/or gas customers of PG&E, SCE, SoCalGas, and SDG&E. This program offers cash rebates for installing energy storage technology at both residential and non-residential facilities. This funding includes prioritization of communities living in high fire-threat areas, communities that have experienced two or more utility Public Safety Power Shut-off events as well as low income and medically vulnerable customers. 

What should you consider while choosing the best storage option?

  • Capacity & power. Capacity is the total amount of electricity that a solar battery can store, measured in kilowatt-hours (kWh). Power rating is the amount of electricity that a battery can deliver at one time. It is measured in kilowatts (kW).

  • Depth of discharge (DoD). A higher DoD means you will be able to utilize more of your battery’s capacity.

  • Round-trip efficiency. A higher round-trip efficiency allows you to get more economic value out of your battery.

  • Battery life & warranty. The general range for a solar battery's useful lifespan is between 5 and 15 years. Your solar battery will have a warranty that guarantees a certain number of cycles and/or years of useful life.