Installing a home energy storage system, such as a Tesla Powerwall, can help you save even more by storing the excess solar energy you generate to use later. It can also help reduce your reliance on the electric grid by providing a backup power source that you can use in the event of an emergency.  The amount of storage that you need depends on your home’s energy usage. A Tesla Powerwall can store up to 13 kilowatt-hours of electricity, which isn’t enough to power your home continuously, but can help keep the most important appliances running.