Battery Uses

Batteries are like a Swiss Army Knife. They can perform many different functions that help both you and the power grid. That is part of the reason why they are important for building a smarter energy infrastructure. Here are a few of a battery's top uses.

Backup Power

One of a battery’s uses is to provide backup power in the event of a power grid outage. To provide this service in a home, batteries are typically wired by a certified installer to an additional, back-up electrical panel that supports items that the customer selects, such as lights, a refrigerator, and select wall outlets. If the power grid goes down, these critical items still receive power.

When a customer pairs a battery with rooftop solar, as shown in the illustration below, the rooftop solar system is able to continue operating during a power outage—providing back-up power for a longer period of time than the battery could on its own. Without a battery, solar systems must shut down during outages to follow approved safety and reliability standards and protocols.

Note: This is a simplified illustration and is not meant to reflect actual power flows or approved system designs for interconnection purposes.

Energy Cost Management

Many business customers have energy rates that change based on the time of day and how much energy they use in a given time period. Batteries can help these customers manage their energy costs by storing energy during low cost times and discharging energy during high cost times.

For most Xcel Energy customers, batteries are still too expensive to provide significant cost savings benefits, but as battery costs decline they will become more attractive.

How it Works:

1. A local factory pays for part of its energy costs based on its highest energy demand in any 15-minute time period during a given month
   
   
2. There are certain times each month when the factory turns on all its equipment at once for a short period of time
   
   
3. That causes its monthly energy profile to look very spiky and a portion of its bill is related to the largest spikes
   
   
4. Using complex software and analysis, a battery system is designed to charge so it is ready to release its energy during the time when the factory’s energy usage is spiking.

Renewable Integration

Solar and wind power are variable sources of energy. They only generate energy when the wind is blowing or the sun is shining. Often the times when solar and wind are generating energy are not aligned with when people are using the most energy. Batteries can store energy from solar and wind and discharge it when it is needed the most.