How battery storage works
A home battery system can serve a similar purpose to a traditional fossil fuel generator, but unlike a traditional generator, there is no fuel to be purchased and stored during an outage. When there is a utility grid outage, a battery storage system can isolate some or all of the household electricity needs (called loads) from the utility grid and continue to provide power to those loads. When utility grid power returns, the backed-up loads automatically reconnect to the grid.
Additionally, if paired with a solar electric system, the battery can be recharged by solar energy. Our Solar + Storage article provides more information about the benefits of pairing a solar electric system with battery storage.
Powering an entire home with a battery system is still relatively expensive, which is why a homeowner may elect to install a smaller battery system to power pre-designated critical loads. For commercial-scale customers, battery storage can provide savings by mitigating the higher costs of using energy at times when electricity from the grid is expensive (high “time of use” rates), or when a commercial property is using significant amounts of power in a short period of time (demand charges). Currently, in Massachusetts, residential customers are largely not impacted by demand charges or time of use rates, though this could change in the future.