A home solar storage battery in a garage.

There has never been a better time to consider solar. Advancements in solar technology have made it more affordable, and advancements in battery technologies are giving customers greater energy independence.

We're happy to announce that, in select U.S. markets, the SunPower® Equinox™ home solar energy system can now be paired with industry leading solar battery storage providers Sonnen or Tesla. This gives SunPower customers a choice when it comes to which home battery product will best meet their energy storage needs.

How Home Solar Batteries Work

A SunPower Equinox solar energy system generates electricity whenever the sun is shining, often making more than a home needs during peak seasons. That excess energy is sent to the grid, and the homeowner usually receives a credit from their utility that can offset the electricity used at night. (See How Solar Net Metering Works.)

While the grid still plays a supporting role, more homeowners are requesting solar-plus-storage so they can have more control over their electricity use.

Solar storage batteries work by taking that excess electricity and storing it. The stored solar energy can be used to complement power from the grid at night or to power essential appliances1 during a power outage. (Check out this battery storage inforgraphic to see how batteries work in five steps.)

Lithium ion home storage batteries usually come in a rectangular white box that’s about 4- to 5-feet high, 6 inches to a foot deep and about 2 feet wide.  They are mounted in an out-of-the-way spot, such as a utility room or in the garage. The bigger the battery, the more power that can be stored. Any excess left over after the battery is charged flows back to the utility.

See if Solar-Plus-Storage is a Good Fit

Keep in mind that most solar homeowners won’t need a storage battery. Usually the power generated by a properly sized home solar system is enough to meet a family’s electricity needs, with net metering covering any electricity used from the grid in the evening or on cloudy days.

While power outages do not routinely impact many households, a home battery can provide you with greater peace of mind, and it’s a clean, quiet alternative to a noisy generator. But do keep in mind that if the power does go out, a home battery is designed to keep only essential appliances1  up and running — not every light or piece of electrical equipment used in the house.

To see if a home battery makes sense for you, visit our new solar-plus-storage savings calculator — the most advanced online tool of its kind in the industry —  to estimate how many solar panels you’ll need based on your energy usage. The calculator also helps homeowners understand how to design their solar system with a battery and how to adjust their system size if they own an electric vehicle.

If you want to purchase a solar system with storage or if you want to add a battery to a recently purchased Equinox system, you can offset 30 percent of your costs by applying the federal Investment Tax Credit. Customers in California and Massachusetts can qualify for additional incentives that can dramatically lower the cost of a battery. But don’t delay. Starting in 2020, the ITC will be reduced to 26 percent and lower in future years.

For Homeowners in Hawaii

A final note: For certain customers in Hawaii, state regulations do not allow solar systems to export electricity to the grid. Solar systems must enter what’s called “zero export mode.” In zero export mode, the solar and battery system do not export excess energy to the grid. SunPower engineered a unique enhancement to the Equinox algorithm that only works with the Tesla Powerwall battery.  If there is a power outage in Hawaii or other areas with zero export rules, the solar system will continue to power the home and charge the battery.

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