Over the past few years, a clear trend has emerged in California. More homeowners who already have solar are adding battery storage to their existing systems. Just a few years ago, batteries were optional. Today, they are one of the most valuable upgrades a homeowner can make.
At Supreme Solar and Electric, we’ve seen a significant increase in homeowners asking about adding batteries to systems that have already been installed. Some of these systems are only a few years old, while others have been producing electricity for well over a decade. The question we hear most often is: “If my solar system is already working, why would I add batteries now?” The answer depends on which net metering program you are enrolled in, your electricity usage habits, and your long-term goals.
For some homeowners, batteries allow them to expand their existing solar system without losing valuable utility agreements. For others, batteries provide backup power during outages. And for many, batteries simply make their existing solar system more valuable than it was before. Let’s examine the three primary reasons homeowners are installing battery storage today.
The Biggest Reason to Add Storage: Expanding an Existing NEM 2 System
The number one reason homeowners are adding batteries today is that they want to expand their existing solar system. This usually happens because their electricity usage has increased since the original installation.
Common reasons include:
- Purchasing an electric vehicle
- Installing a pool
- Running the air conditioner more often
- Adding onto the home
- Switching gas appliances to electric
- Growing family energy usage
Their original solar system was sized correctly when installed. The problem is their energy usage has changed. They now need more solar production. Under California’s current rules, simply adding panels is not always best. Often, it is better to install a new solar system with battery storage as a non-export system.
What Is a Non-Export Solar System?
A non-export system does exactly what its name suggests. The new solar system is designed so that it does not send electricity back to the utility grid. Instead, the energy follows a different path. First, it powers the home.
If there is additional solar production available after meeting the home’s demand, that extra energy charges the battery. Rather than exporting electricity to the utility, it stays on site. This allows homeowners to increase their solar production without changing how their existing NEM 2 agreement operates.
How the Existing System Works Together
One of the biggest misconceptions is that everything changes once a battery is added. That is not the case. The original NEM 2 solar system continues operating exactly as it always has. If it produces excess energy, it can still export power to the grid according to its existing agreement. The newly added solar system operates differently.
Instead of exporting electricity, it stores excess production inside the battery. This creates a very efficient combination. The existing system continues receiving export credits. The new system increases daytime production and stores excess energy for nighttime use. Together, the systems allow homeowners to expand their production while preserving the value of their existing net metering agreement.
The Second Reason: Greater Energy Independence
The second major reason homeowners add batteries is simple. They want more control over their electricity. Even homeowners with existing solar systems still rely on the utility at certain times. Adding battery storage reduces that dependence. Instead of immediately buying electricity from the grid once the sun goes down, homeowners can continue using the electricity they generated earlier in the day. This creates a much greater level of energy independence. For many homeowners, that peace of mind is just as valuable as the monthly savings.
Batteries Provide Backup Power
Another major benefit is backup power. Without batteries, most traditional grid-tied solar systems automatically shut down when utility power goes out. This is a safety requirement that prevents electricity from feeding back into utility lines while crews are making repairs. Adding battery storage changes that. Battery systems equipped with backup capability can disconnect from the utility and continue powering the home during an outage.
Critical loads such as:
- Refrigerators
- Internet
- Lighting
- Garage doors
- Medical equipment
Essential outlets can continue operating while the neighborhood remains without power. For many homeowners, especially those living in areas with frequent outages, this alone makes batteries worth considering.
Better Use of Time of Use Rates
Batteries also allow homeowners to better manage Time of Use electricity rates. Homeowners on NEM 2 receive export credits based on when electricity is sent back to the grid. Unlike NEM 1, which provided nearly one-for-one retail credits regardless of time, NEM 2 introduced time-based pricing. Electricity exported during peak periods generally receives a higher value than electricity exported earlier in the day.
Peak hours typically occur between 4 PM and 9 PM. These are the same hours when homeowners usually return home from work. Air conditioners begin running. Laundry starts. Dinner is cooked. Electricity demand increases. Because of this, utility companies place a higher value on electricity during those hours.
A battery gives homeowners flexibility. Instead of immediately using or exporting electricity, they can decide when that stored energy provides the greatest financial benefit. Sometimes that means using the battery instead of purchasing expensive electricity from the utility. Other times, it may make sense to export energy during periods when export values are higher. That flexibility simply did not exist with a solar-only system.
The Third Reason: Preparing for Net Metering Expiration
The third major reason homeowners are adding batteries is that their existing net metering agreement is approaching expiration. Many homeowners installed solar systems under NEM 1. These agreements generally last 20 years. Once that agreement expires, the homeowner transitions to California’s current program, NEM 3. That transition represents one of the biggest changes in California solar.
What Happens When NEM 1 Expires?
Under NEM 1, homeowners received highly valuable export credits. When they move to NEM 3, those export values decrease dramatically. Instead of receiving credits close to retail value, export values often fall by approximately 80 percent. That is a significant change. Without battery storage, homeowners suddenly find themselves exporting valuable electricity for only a fraction of what it was previously worth.
Batteries: Restore the Savings Strategy
Fortunately, batteries completely change the strategy. Instead of exporting excess electricity for low-value credits, homeowners store that energy on-site. Then, once the sun goes down, the battery powers the home. Rather than buying expensive electricity from the utility every evening, the homeowner uses electricity they already produced themselves. The focus shifts from exporting electricity to maximizing self-consumption. That is exactly how modern solar systems are designed today.
Why Batteries Have Become So Popular
Battery technology has improved significantly over the past several years. Today’s systems are more reliable. They have better monitoring. They integrate seamlessly with solar production. Most importantly, they align perfectly with California’s current utility structure. The goal today is no longer to maximize exports. The goal is to maximize self-consumption. Every kilowatt hour stored in a battery is one less kilowatt hour that needs to be purchased from the utility later. That is where the savings come from.
Is Adding Batteries Worth It?
For many homeowners, the answer is yes.
Especially if:
- Your electricity usage has increased
- You want backup power
- You are approaching the end of your NEM 1 agreement
- You want greater energy independence
- You are adding electric vehicles
- You want to reduce peak utility purchases
Every home is different, but batteries have become one of the most effective upgrades available for existing solar systems.
Battery Storage Puts the Power in Homeowners’ Hands
The reason more homeowners are adding battery storage today is simple. The way California utilities value solar electricity has changed. Instead of relying on the grid to store excess energy, homeowners are now storing that energy themselves. For homeowners on NEM 2, batteries allow system expansion while preserving existing agreements through properly designed non-export systems. For homeowners looking for backup power, batteries provide peace of mind during outages. For homeowners approaching the end of NEM 1, batteries create a new strategy that replaces lost export value with self-consumption.
In every case, the objective is the same. Generate your own electricity. Store the excess energy you produce. Use that energy when your home needs it most. And rely on the utility as little as possible. That is why battery storage has become one of the fastest-growing upgrades for existing solar systems throughout California, and why more homeowners are choosing to add batteries every year.
Take the power back with help from the Fresno solar installers at Supreme Solar. Let our solar energy system installation professionals help you preserve your energy independence and power your home in Fresno.