As solar power becomes increasingly popular, more homeowners are exploring how they can store more of the energy their solar panels generate with battery storage. In fact, the U.S. was the second biggest energy storage market last year and residential homes played a large role.

Dan Glaser, a senior sales engineer for Panasonic, says that a desire by homeowners to be more self-sufficient is driving the demand for energy storage.

“Some of the interest is from homeowners who want access to backup power during grid outages,” he says. “In other cases, people are interested in strategically using stored power, especially if they live in areas where they can’t put it back on the grid.”

An energy storage system, which is an on-site unit for storing energy generated by your solar panels, makes this possible. Glaser says that asking these key questions before you buy ensures you find the right system for your home and budget.

What components do you need for a proper battery storage system?

A standard battery storage system (also referred to as energy storage or solar storage systems) comprises batteries for storing the power and at least one inverter for converting the energy into a usable form. In some instances, there's also a software component for monitoring energy usage remotely. Glaser notes that you can purchase one unit that includes all these components, often in conjunction with your solar panel purchase. Or you can buy a standalone system to retrofit an existing photovoltaic (PV) setup. 

Whichever you decide, Glaser says this is not a DIY project. “The technology is complex enough that you want a professional installer who is familiar with how it works, and aware of local codes and regulations.”

AC or DC battery storage? 

These terms — alternating current (AC) and direct current (DC) — refer to the direction the power flows. Solar panels produce DC electricity and that’s what most batteries store. However, your house and most of the appliances in it require AC power.

The system that works best for your home depends on whether you already have an existing solar power system. While an AC-coupled system requires two inverters and is often less efficient, if you have a pre-existing solar setup, then it’s the only option available.

If you are purchasing a new PV system, you’ll want to evaluate both AC and DC-coupled energy storage solutions. DC coupled solutions typically have fewer efficiency losses. However, if you choose a microinverter or optimized solar module, then an AC-coupled system may be the best option. Every installation is unique, so you’ll want to consult your installer during your decision-making process. 

How much power do you need to store?

The battery storage system size your home needs requires a thorough energy audit and detailed analysis by an experienced contractor. You can roughly estimate how much storage you'll need based on your daily electricity usage. The average for a U.S. residential utility customer is about 28 kWh per day. Usage can vary depending on certain factors, such as the climate where you live. In this case, to provide back up power for an entire house, you'll need a system producing at least 28 kWh.

The actual analysis for your home requires detailed math and customization. It's also worth noting that many residential storage solutions only offer a single system size. This keeps installation simple. However, the tradeoff is you can end up with an undersized or oversized system. An experienced installer can help determine which size works best.

Are there ways to decrease the cost?

Energy storage is a smart investment that pays for itself over time. But finding ways to save money at the outset can make your project more feasible. Entry-level energy storage systems typically cost between $10,000 and $25,000, Glaser says, with larger capacity systems falling on the higher end of that range, or greater. Whole-house backup can cost more, depending on what loads you require during an outage. There are many local incentives and tax breaks too, so be sure to consult your authorized installer on the best path forward.

Homeowners can lower some of the costs with tax credits, manufacturer rebates, and incentives from their local utility companies. For instance, with the federal solar tax credit, you can deduct 30% of the cost of your energy storage system (and there's no upper limit). Investigate what’s available locally in your area and you may be pleasantly surprised.

Lastly, be sure to inquire about warranties on your storage system. “You want to go with a trustworthy brand,” Glaser says. “Look for a company that’s been around for a long time — these systems last decades and you want to work with a company that will as well.”

Building an on-site battery storage system ensures you have the power you need — when you need it most. Approach the buying process thoughtfully, and you’ll end up with an energy system that fits your family's needs and budget.

Visit this page to learn more about the benefits of solar battery storage and find out if it's right for your home. 

Top Solar Battery Questions—Answered!

If you’ve heard about the benefits of solar battery storage and are thinking about adding one to your home, you probably have a few questions about how energy storage works and why it’s worth the investment. 

SouthFace Solar & Electric is a leading solar battery installer in Arizona, and we’re here to help you understand this impressive technology. Keep reading for answers to the most common questions we hear about solar battery back up power for Arizona homeowners. 

How do solar batteries work? 

A solar battery is kind of like a generator—it sends power to your home when the electric grid is down. But unlike a generator, solar batteries don’t run on fossil fuels like propane or natural gas. Instead, they run on stored solar energy. 

During the day, your solar panels will typically produce more electricity than you need to power your home. In a traditional solar panel system, the excess energy your panels produce would either be sent to the electric grid, or it would go to waste. With a solar battery, you can store excess solar energy and draw on it when the sun isn’t shining, during peak demand periods, or during a power outage. 

Can a solar battery power your house during an outage? 

Yes! A solar battery can power your house during an outage. 

Residential solar panels don’t provide back up energy on their own, and all grid-tied solar systems are automatically turned off during a power outage to protect utility workers from unexpected power surges. If you have a solar battery, however, your solar panel system can continue to operate while disconnected from the grid. So, during the day, you’ll be able to generate electricity with your PV panels while the power is out while at night you can rely on power from your solar battery backup. 

How long can a solar battery power your home? 

The amount of power a battery storage system can provide depends largely on size. Some solar batteries have the capacity to power small appliances and essential loads like your refrigerator for a few hours at a time. Larger battery systems can power your entire home for extended periods of time. SouthFace Solar & Electric can help you decide how much backup power you need and recommend the right size battery or batteries for your home. 

What are the benefits of solar battery backup? 

Installing solar panels and back up power for your home has a lot of benefits, and SouthFace Solar & Electric can help you take advantage of them all!

Benefits of solar batteries include: 

• Power for your home during an outage 
• Access to solar power at night and on cloudy days 
• Avoiding demand response charges by switching to battery power
• Using more of the renewable energy your solar panels generate
• Qualifying for solar battery incentives 

Do solar batteries save you money? 

Installing a solar battery can help you reduce your electricity costs even more than with solar panels alone. 

Solar panels only work when there is sunlight available, which means solar power users have to rely on grid-generated electricity later in the evenings during peak demand periods, at night, and on especially cloudy days. Electricity rates tend to be higher in the evenings, which means you’re likely paying even more for electricity during these times. 

With a solar battery, you can save the excess solar power that your panels generate during the day and use it to power your home at night, on a cloudy day, or during demand response times. This reduces your reliance on the grid and helps you save money on electricity. 

What types of solar battery storage are available?  

There are several types of solar batteries available, with options for partial or whole-home backup and different chemistries from lead acid battery to nickle-iron, to lithium ion batteries. SouthFace Solar & Electric installs solar batteries from top brands like LG Energy RESU, Iron Edison, Blue-Ion and more. We can help you decide what type of battery storage is the best fit for your needs. 

Are there incentives for solar batteries in Arizona? 

Wondering about solar battery tax credits and incentives? We have good news! Through the APS Solar Battery Pilot, APS customers can earn a solar battery incentive worth up to $3,750. Solar batteries can also qualify for the federal solar tax credit. The solar tax credit is in its last few years and will be reduced in 2023 before being eliminated for residential solar in 2024, unless this tax credit is extended. The sooner you schedule your solar plus battery storage installation, the more you stand to earn through solar incentives.