With its legacy of reimagining existing products (along with the recently announced battery storage incentives in the Inflation Reduction Act), the Tesla Powerwall is in high demand with homeowners throughout California.
Powerwall is an integrated battery system that stores the energy generated from your solar panels to power your home during evenings, cloudy days and grid emergencies. Your system will detect a power outage and utilize the stored energy so you can continue using power and select appliances.
Here’s everything you need to know about the Tesla Powerwall, including how it works and what its key benefits are so you can make an informed choice about adding one to your home.
How Much Does the Tesla Powerwall Cost?
The Tesla Powerwall starts at $8,500 before installation and will typically cost between $12,000 and $16,500 for a full storage system installation (before incentives).
The total cost includes the battery, an inverter (to change DC current to AC current),and any additional equipment costs and estimated installation costs. The cost of installing a home battery isn’t as simple as looking up the price for an individual component—for example, your battery. In fact, the cost of installation can vary widely depending on your electrical setup.
If you want to install a solar-plus-storage system, it’s important to understand that the actual Tesla Powerwall cost is only one part of the equation. A residential 5 kW solar energy system costs between $9,000 and $15,000 depending on where you live and the type of solar panels you choose.
Installing a solar system and Tesla Powerwall can be an expensive but worthwhile investment, especially if your electricity prices are high. Whether or not the Tesla Powerwall makes sense for you can depend on how your utility company structures its rates, along with your reasons for considering a solar power battery.
For instance, if you want to become energy independent and can install several Powerwall batteries to maximize your energy storage capability, then investing in one is worth the time and money. Home batteries can also provide peace of mind protection during power outages as well as help the environment by reducing your carbon footprint.
Depending on where you live, you may be eligible for incentives or tax credits that would decrease the cost of your home energy storage installation. If you live in California, for instance, you could get a cash rebate that will offset a portion of your home battery costs through the Self-Generation Incentive Program (SGIP). Several states are considering incentives to promote the use of batteries, and some already offer rebates for Tesla’s Powerwall. It’s important to ask your solar advisor about your options during your solar consultation.
How the Powerwall Works
The Powerwall is a great addition to solar panel systems, but can it store enough energy to power a home? In short, yes—installing a storage solution like the Tesla Powerwall with a solar energy system allows you to maintain power throughout the day and night, as long as you store enough power from your solar panels when the sun is shining.
As with many other home battery products, the Tesla Powerwall is sized for day-to-day use at your home and is often paired with a solar panel system.
When your solar panels produce more clean energy than you need, you can store the excess in a battery system rather than send it back into the grid. On cloudy days or evenings, when your solar panels don’t produce enough electricity to meet your home’s needs, you can use the electricity stored in your battery instead of buying it from your utility company.
Key Things to Know About the Tesla Powerwall
Described as a “rechargeable lithium ion battery with liquid thermal control,” the Tesla Powerwall is a small-scale battery designed for home energy storage. The original Powerwall was introduced in April 2015, and the Powerwall 2.0 versions were announced in October 2016 and November 2020.
When evaluating energy storage solutions, it’s important to understand your options and compare the technical specifications and metrics for each. Important technical details of the Powerwall include the size of the battery (power and capacity), its chemistry, depth of discharge, and its roundtrip efficiency.
Size
The Powerwall comes in only one size: 14 kilowatt-hours (kWh). There are two important metrics to keep in mind when comparing the Powerwall’s capabilities with other home storage options: power and usable capacity.
Power is measured in kilowatts (kW) and determines how much electricity your battery can output at once. Usable capacity is measured in kilowatt-hours ( kWh) and is the maximum amount of energy that can be stored within your battery on a full charge. The Tesla Powerwall has a maximum power rating of 7.0 kW and stores 13.5 kWh of usable capacity.
The battery’s power determines how many appliances can run at the same time, while its usable capacity determines how long those appliances can run. Batteries with a higher power rating can run more robust appliances or power many appliances at once. Batteries with a higher usable capacity can store more total energy, so you can use your devices for longer periods of time without recharging.
The Powerwall system is also modular, so you can add multiple Powerwalls to meet your storage needs. For example, if your home has high energy demands or usage patterns, multiple Powerwall batteries can be installed. According to the Tesla website, you can combine up to 10 Powerwall batteries together into one massive storage system.
Basic Functionality
The functionality of one solar power battery is not necessarily equivalent to that of another. Some batteries offer excellent off-grid capabilities, while others provide special software solutions for maximizing rate arbitrage.
Here are important Tesla Powerwall qualities to know:
Backup Power
Tesla has made an effort to make its battery storage solution compatible with the most common brands and types of off-grid and hybrid inverters. This means once your system is qualified, a Tesla Powerwall Certified Installer will be able to provide backup power for your home when the grid goes down.
Chemistry
The Tesla Powerwall is a lithium-ion storage product composed of lithium nickel manganese cobalt oxide (NMC). NMC batteries are one of the most common types of lithium-ion batteries and for good reason. Relative to other technologies, NMCs offer a high level energy density (the amount of energy that can be stored in small spaces) along with increased safety.
To learn more about the different types of lithium-ion batteries available, here’s an overview of battery chemistry differences.
Performance Metrics
Two important factors to consider when evaluating the performance of a solar battery are its depth of discharge and roundtrip efficiency.
Depth of discharge (DoD) is a measure of how much of your battery’s energy has been discharged compared to its overall capacity. Because a battery’s useful life decreases with each charge/discharge cycle, many manufacturers specify maximum depth of discharge levels for optimal performance. Generally, a battery with a higher depth of discharge is considered to be a better quality product. The Powerwall has a depth of discharge of 100 percent, making it one the safest and most advanced lithium-ion batteries available.
Roundtrip efficiency measures how much electricity is lost during the battery’s charge/discharge cycle. The higher the efficiency rating of a battery, the more it’s able to efficiently convert incoming electricity into stored energy and back again. The Tesla Powerwall has a 90 percent roundtrip efficiency; for every 10 kilowatt-hours (kWh) of electricity you put into the battery, 9 kWh will be available to use.
What is the Warranty on Tesla Powerwall?
The Powerwall comes with a 10-year warranty and Tesla guarantees that it will retain at least 70 percent of its charging capacity during that time. Like all rechargeable batteries both large and small, the Powerwall will lose some of its ability to hold a charge over time. For example, look at the difference in battery life between a brand-new smartphone and one that’s a few years old. As you use and recharge your phone’s battery, it gradually loses some of its ability to hold a charge.
Likewise, your Powerwall’s battery life will deteriorate as well. That drop in power is not a product flaw. All batteries experience it to some degree after extended use, whether the battery is used for an electric vehicle, a home energy storage system or a rechargeable AA battery. This is why Tesla offers an extended warranty on its batteries that guarantees a certain percentage of storage capacity ten years from now.
Can You Go Off-Grid With the Tesla Powerwall?
While installing a solar-plus-storage system for your home is an excellent way to take control of your electricity bill, you’re still technically connected to your utility grid. Going “off the grid” with solar batteries is more expensive and complicated than most people realize.
The Powerwall and most other residential batteries have only enough capacity to hold a few hours of electricity. If you want to ensure that your property will have power for days at a time, you’ll need to install multiple Powerwall batteries together so you can take advantage of their combined storage and usage capabilities. This is something to review with a solar advisor to ensure you will have the backup you want and the stored energy you need to power your home 24/7.
Conclusion
Adding energy storage to your home is a great way to protect yourself against rising energy costs, grid outages and more. As a Tesla Powerwall Certified Installer, we can provide the best home battery recommendation based on your current energy usage.
If you’re ready to see how much money you could save with a Powerwall in your home, contact us today for a free customized quote.