Protect Yourself From Blackouts

How Solar + Storage Works During A Power Outage

Sunnova SunSafe® automatically manages the energy flow and will be designed to help meet your home energy needs. Unlike a solar-only system, you can produce solar energy during the day during a power outage; the battery stores excess energy for use at night.* When charged at 100%, you can power your most needed lights and appliances for approximately 10-13 hours*, depending on battery(s) capacity and your usage.

  • During The Day (Power Outage) - Unlike a solar-only system, you can continue generating and storing solar energy during the day; any excess will be sent to the battery. Solar energy will be used to power your most needed lights and appliances.*

  • At Night (Power Outage)  - Your most needed lights and appliances will be powered by any energy stored in your battery.*

Sunnova + SunSafe® Energy Storage System

During a power outage, your home solar system will not work unless you have a battery!

Tesla Powerwall


  • Increase Your Energy Independence

    Reduce the electricity that you get from your utility. Power your home with the solar energy stored in your battery, even when the sun goes down.2

  • Resilient Backup Power

    During a power outage, your battery can power your most needed lights and appliances, and sometimes your whole home.1

  • Battery Protection

    Your Tesla Powerwall comes with a limited manufacturer warranty for the term of your agreement. If you’re a Sunnova +SunSafe® customer, we take care of maintenance and repairs.3 Even after your agreement ends, the battery will still have capacity as outlined in your warranty.4

  • Protection from Peak Rates

    If you live in a market with time of use (TOU) rates, your battery will be automatically configured to protect you from peak rates and maximize your net metering credits.


Frequently Asked Questions


Power outages

In cases of extreme weather events or utility-mandated outages, our battery storage solution allows your existing home solar system (whether it’s a Sunnova system or not) to continue producing energy – even during power outages.1

Maximize the economic benefit from your solar system

If you’re a Sunnova customer, we will configure your battery to make sure you get the maximum economic benefit from your solar + storage system.2 For example, your battery configuration may be different if you live in a time of use (TOU) market, net metering market, or if you have other local incentives.

Increase your Energy Independence

No matter where you live and what your local utility conditions are, a solar storage battery combined with smart energy consumption can help you reduce the amount of electricity you pull from the grid.

Which battery is best for your home solar system?

While solar storage batteries may look the same, the inner-workings of the technology may be very different. The most often considered choices are lead-acid or lithium-ion.

  • Cycle life - how often a battery is charged and depleted - Lithium-ion batteries are made to handle several times the number of cycles as lead-acid batteries. The more you cycle a battery, the leff effective the battery becomes.
  • Capacity – how much energy can be stored and discharged by the battery - Lithium-ion batteries are proven to have significantly higher energy density than lead-acid. This means that lithium-ion batteries can store more energy in the same physical space than lead-acid batteries. For emergency solar backup power, it will take several heavy lead-acid batteries to match the capacity of one large lithium-ion battery.

What is the life of a solar storage battery?

For everyday use with home solar, lead-acid batteries often last under two years, while lithium-ion batteries can last 10 years, depending on usage and other factors. At Sunnova, we offer state-of-the art Tesla Powerwall 2 lithium-ion batteries. After 10 years, your Tesla Powerwall warranty guarantees that your battery will still retain 70% of its charging capacity, so you can keep your battery for years to come.1

Will my home solar system work in a power outage?

If your home solar system is connected to your utility and you do not have a battery, your home solar system will not work during a grid outage. You will not be able to produce or consume solar energy while the grid is down.

During a power outage, your home solar system will automatically turn off. This is to prevent solar energy flowing through the utility grid while repair crews fix any downed power lines or other failures. When the power comes back, your home solar system will automatically turn back on.

Backup Energy with Solar Battery Storage

During a power outage, a home solar system with a battery can function as a nanogrid.

When the grid is down:

  • A battery can power your essential lights and appliances.2
  • Your solar panels can keep generating power from the sun.2 There is no risk of sending excess solar production to the grid since excess solar production will charge the battery.

* EIA - Profile Data.
1. The amount of power available from the battery during a power outage is limited, depending on the loads connected, customer usage and battery configuration (i.e. batteries in certain areas may be set up to provide you with the best economic benefit, which may affect the amount of back-up power available). Solar systems and/or batteries may require repairs after weather events and such repairs may be delayed due to forces outside of our control. No assurances can be given that the solar system or the battery will always work. You should never rely upon either of these to power life support or other medical devices.
2. Applicable to all battery configurations except backup power.
3. At the end of 10 years, the warranty provides that the battery will retain at least 70 percent of its capacity. At the end of 15 years, the warranty provides that the battery will retain at least 60 percent of its capacity.
Refer to the Limited Warranty in your agreement for complete warranty terms and limitations. Your solar system production will vary based on weather and other factors. Solar system’s cumulative production will be evaluated to validate annual production guarantee. Refer to your agreement for details. Restrictions and limitations apply. The service agreement can be transferred to the new homeowner. Sunnova’s approval required. Some restrictions apply.