Batteries for storing solar energy have recently gained a surge in popularity. With this hype, it is common for misleading or confusing information to become widespread. In this blog, we break down the very basics of batteries so that you can make an informed choice for storing solar energy at your home or business.

Energy storage in the form of batteries has been a source of rapid development in recent years. The rise of lithium ion batteries has allowed for energy storage equipment to be smaller and more powerful than previous technologies. These are the same batteries that are in your cell phone and laptop. It makes sense that the same technology that helped fuel the smart phone revolution would also transform solar energy storage.

Batteries are used to store energy produced at one time and deliver it at a later time. Photovoltaic (PV) solar systems produce electrical energy during the day, when the sun is shining, but do not produce any energy when it’s dark. Since households often use more electricity after the sun has set, they have two evening options: pull electricity from the grid or use stored energy from batteries. Today, most solar systems are tied to the grid, effectively using the utility as a “battery.”

Batteries can provide customers with the flexibility to consume their solar energy later during the day, when electricity rates are the highest. This can help reduce the demand on the grid in the evening and help customers get the most value from their solar electricity.

In the event of a power outage, batteries with a backup function can also provide resilience and independence to solar customers by disconnecting the home’s essential appliances from the grid and forming an internal “micro-grid” that will allow the solar panels to continue recharging the battery, which will discharge energy to the home as programmed.

(1) Resilience

If you live in a place with an unreliable grid where outages are common, battery backup systems can save you a lot of headaches and trouble. Even here in a populated area like Santa Barbara, where Southern California Edison’s transmission lines are old and liable to failure, there is potential for power outages that could leave SCE customers without power.

It is important to note that your solar system will not operate during a blackout without batteries. There is an automatic shutdown feature included to protect utility workers.

In the event of an outage, appliances that require electricity such as refrigerators, HVAC systems, medical devices, aquariums, wine cellars, internet routers, and computers would all be left without power. This can create quite a discomfort for both residences and businesses. Besides being left uncomfortable in the cold dark, power outages can also be a financial burden. For households, this means having to throw away a freezer full of food. For businesses, this means having to put operations on hold for a day or losing valuable data.

A building with an adequately sized battery backup system will be able to handle these outages much easier, without the potential for heavy financial losses. This solution gives solar customers both independence and resilience from the grid during its ever-more-frequent outages, by having access to uninterrupted power.

(2) Independence

Another way to utilize a battery is by taking control of your electricity cost and reducing your bills with consumption management. You can discharge your battery after sunset to use the stored energy produced by your solar system during the day. This is a great strategy for both residential and commercial customers to avoid peak hour rates. You can rely on the grid only when you decide that it makes sense and become independent from the grid when desired.

(3) Control

Utility bills have significantly increased over the years. Not only have the utilities consistently been increasing their energy rates (i.e. the price of the kWh), but they have even more dramatically increased all the other fixed costs included in your bill (such as operation and maintenance, transmission, and infrastructure costs), as a way for the utility to meet its revenue requirements and provide payouts to shareholders.

As utility costs are likely to keep increasing in the future,  having a battery and consuming your stored solar energy when needed will help reduce the demand on the grid and protect you from higher bills. The more the utility increases its rates, the more solar customers will save in avoided costs.

Most batteries on today’s market are lithium ion, but some are made with more environmentally responsible and safer chemicals than others. Brighten Solar Co. chooses to install Cobalt-free batteries that use Lithium Ferro-Phosphate (LFP) chemistry and here are the reasons why:

•  They are a safe choice for your home as they do not risk thermal runaway
•  They are landfill safe and some are 100% recyclable
• They are an ethical choice, as Cobalt is one of the worst ethically mined minerals
• They are durable as they have a warranty of 15 years

You can learn more about the different battery chemistries and the benefits of Cobalt-free batteries in this blog post.

(1) A grid-tied battery system allows solar customers to consume their stored energy from the battery when needed to power home appliances and avoid peak TOU rates. It allows customers to get the most value from their solar electricity by reducing export to the grid and maximizing self-consumption during the times when grid electricity is the most expensive. This results in a much higher avoided cost than a solar-only system. However, a grid-tied battery system does not have a backup function and will not provide resilience or full independence to the home in case of a power outage.

(2) A battery backup system provides both independence and resilience from grid outages. In this situation, the equipment work together to disconnect from the grid and form an internal micro-grid that will allow the solar panels to continue recharging the battery, which will discharge energy to the home as needed. It requires additional equipment and electrical work, such as a smart switch to disconnect from the grid, a backup subpanel where essential loads are isolated, and the relocation of existing circuits. Adding such equipment to a grid-tied battery system can be done at any time and will result in an additional cost.

In short, yes there is! But these incentives have specifications and expiration dates:

• Federal Investment Tax Credit

The Federal Investment Tax Credit (ITC) can save consumers up to 30% of the total cost of their solar system, optimizing their investment. Batteries with a capacity of at least 3 kilowatt-hours are also eligible for the credit.

*The ITC will begin stepping down to 26% at the end of 2032, then to 22% at the end of 2033, and will expire at the end of 2034 for residential applications.

• Self-Generation Incentive Program

This California incentive has been around since 2001 and made available by the California Public Utilities Commission for “behind the meter” technologies like batteries but has had a recent overhaul to make it easier to claim the benefits. PG&E, SCE and SDG&E customers are eligible for a rebate per kilowatt-hour of home battery storage. This incentive can offset the majority of your battery cost! The available incentive amount depends on the battery size and the status of the incentive in your utility area: as more energy storage is purchased, the incentive value steps down. You can check the current status at www.selfgenca.com/home/program_metrics/

There are many considerations to take in when choosing a battery: how much storage you need, what your budget will allow, and the current state of incentives available. While financial value is important, we strongly recommend evaluating the quality of your investment in batteries before making a decision. A less expensive battery may save you money upfront, but if the warranty is full of holes or the manufacturer goes out of business, you may find yourself in a costly or frustrating situation.

Solar and energy storage are long-term investments in which quality and safety outweigh quantity and discounts. Be sure to ask your installer details about the manufacturer, the warranty provided, and the chemical compounds in your battery options.