What You Need to Know About Energy Storage and Solar Batteries

Most people take for granted the role that batteries play in keeping our homes and communities powered. But energy storage, and batteries in particular, are essential to our clean-energy future and we’ll cover the reasons why in this post.

What is Energy Storage? What is a Solar Battery?

The primary function of solar energy storage is to capture and store the power generated by solar panels for later use. The ability to store energy for later use provides a number of benefits, from financial savings to serving as backup power during power outages.

The main advantage of installing a solar-plus-storage energy system is that it will allow you to use your solar electricity at any time—even when the sun isn’t shining. When you install a solar panel system without adding home batteries, excess electricity produced by the panels is sent back to the power grid. With energy storage, you can store and draw that energy to use when the sun goes down and you’ll only pay for the energy you draw from the grid after your battery is depleted.

Are a Battery and Energy Storage System the Same Thing?

Not always! While a battery is a form of energy storage, not all forms of energy storage are batteries. In residential applications, a battery is the most common form of energy storage, so both terms are used interchangeably.

For large-scale businesses and the electricity grid as a whole, energy storage often means using technologies other than just batteries. These include technologies such as pumped hydropower or hydrogen produced from fuel cells.

Why are Batteries So Important for Clean Energy?

One of the critical components of a clean energy future is batteries, because they’re able to match variable energy supply with demand.

The importance of this requires information about the differences between producing electricity with fossil fuels versus clean energy resources like wind and solar.

The Electrical Grid is Good at Generating Electricity with Fossil Fuels

The electrical grid is a network of poles, wires and power plants that distributes electricity to our homes and businesses. More importantly, the design of the electrical grid was intended to match electricity production and demand. The grid’s ability to anticipate when and where electricity is needed, generate the precise amount of energy necessary (plus some extra for safety), then deliver it exactly where it needs to go within seconds is what makes our modern lives possible.

In the past, fossil-fueled power plants (like coal and natural gas) have been the most cost-effective and resource-efficient way to keep this delicate balance operational. Simply put, when the electricity grid operator predicted that more people would be using more electricity (for example, on a hot summer day with many homeowners using the AC unit), they could call on power plants burning coal or gas to produce extra energy.

When those power plants were running at full tilt, the grid operator could tell another power plant to start burning fuel. When demand is low at night, power plants call the grid operator and ask that they produce less electricity. This is how supply is adjusted to meet demand.

The Electrical Grid Isn’t Good at Integrating Renewable Energy

Imagine a scenario where you can predict how much electricity your power plants will generate, but you can’t control when that will occur. To continue providing electricity to people when they need it, you will either:

  1. Shift your demand for electricity to occur when power plants are most efficient, or
  2. Design a system to store electricity when it is produced so that it can be used later, during periods of high demand.

In essence, this is the scenario playing out with renewable energy technologies and part of the reason some grid operators have been reluctant to embrace them wholeheartedly in the past. Solar power is most efficient during the day, but produces no energy at night. In the same way, wind produces electricity when the wind is blowing, but not when it stops.

Today, we can predict how often and how much sunlight and wind will be available for any given day far more accurately than ever before. We can even predict how much clean energy solar and wind can produce down to the minute long before it happens. However, we can’t alter the sun’s schedule or command when the wind blows, meaning we’re limited in our ability to control when these energy sources produce electricity.

How Energy Storage Helps Renewable Energy

This is where energy storage systems can integrate more renewable resources. Energy storage can help balance supply and demand by storing the energy produced by wind turbines and solar panels when there is an abundance of it, then releasing it back into the grid at peak times to meet demand. In order to meet its ambitious clean energy goals at the federal and individual state levels, including those introduced in the Inflation Reduction Act, America needs help from energy storage.

Types of Energy Storage Systems

Today, when people discuss energy storage, they usually refer to home batteries—especially when paired with a solar energy system. However, batteries are only one form of energy storage and they’re not the first technology that’s provided solutions to keeping electricity on the grid. That being said, the most efficient and applicable kind of energy storage for most people is electrochemical—that is, a solar battery.

Electrochemical Storage

Electrochemical storage, or battery storage, is the most common one people are familiar with. Electrochemical storage includes a wide range of battery types—from lithium ion and lead acid to even vanadium flow batteries. These batteries are used in many forms, including the AA and AAA batteries, your cell phone and even the battery that powers your car.

Because electrochemical storage is so compact, you might be able to guess its primary benefit: storing energy in a small space. These types of batteries can be made in a variety of shapes and sizes, with all having extremely high power densities—which means they pack a lot of punch for their size. Because of these benefits, electrochemical storage devices are often used in businesses and homes with solar panels.

Gravitational Storage

Energy storage has provided benefits to the grid in the form of gravitational storage for decades. The most common form of this is pumped hydropower storage. This is when water is pumped uphill into a reservoir and then released to flow back downhill through turbines, generating electricity.

By pumping the water uphill at times when electricity is plentiful and cheap, then running it back downhill again when there’s a shortage of power or its cost has increased, pumped hydro can help power the grid by providing large-scale storage of excess electricity. The best-known example of this technology is at Niagara Falls, where turbines harness the enormous power of falling water. Californians may be familiar with the “pumped storage” system just off Interstate 5 along the Grapevine north of Los Angeles.Here, the Los Angeles Department of Water and Power uses Castaic Lake, as the lower reservoir in a “pumped storage” system that also includes Pyramid Lake.

Although pumped hydropower is the most widely used form of gravitational energy storage, other options exist. Some innovative technologies are designed to mimic the way gravity works by suspending heavy objects and then releasing them, creating a flow of energy. Other technologies that are similar involve stacking blocks.


Mechanical Storage

Mechanical storage is another early form of energy storage, with flywheels being the most common form. It’s similar to a wind-up toy: you store energy by winding it up, and then release that energy by letting the toy unwind. Flywheels have not yet been widely adopted on a large scale, but they are capable of releasing energy very quickly—making them useful in many applications. 

Compressed air energy storage is another form of mechanical storage. Compressed air systems are used to compress a large volume of air into smaller tanks. Compressed air energy storage systems work by pumping air into an underground cavern so the pressure of the stored air increases. The system then uses pressurized air to produce electricity in a slow or fast release.

Thermal Storage

Electricity isn’t the only element that can be used in energy storage systems: thermal energy can also be harnessed for use. For example, you can heat your hot water tank overnight when electricity is cheap and then use the pre-heated water in the morning—when demand for power is high—to save money and reduce the strain on the electrical system. The same can be achieved with cooling freezers,  ice blocks, and AC systems.

Creating Hydrogen with Fuel Cells

One way to store energy for later use is by converting it into a liquid fuel, like hydrogen. Fuel cells convert renewable energy sources (such as solar or wind power) into a fuel that can be used to power industrial processes – even forklifts. The best part of the process is that  when you burn hydrogen, there are zero carbon emissions.

Despite the limited deployment of fuel cells and hydrogen technologies so far, many people in the energy industry are optimistic that these technologies will play a big role in creating a clean energy future.

Coming Soon: Seasonal Storage

One energy storage technology under development is seasonal energy storage: both storing large amounts of electricity and storing it for long periods of time. The use of seasonal storage has the potential to revolutionize how renewable energy is integrated into the electrical grid. For example, you can store excess solar energy produced during the summer to help meet demands in the winter when sun isn’t as strong.

Investing in a Home Solar + Energy Storage System

Energy storage is the key to not only unlocking the full potential of solar and wind power, but also the key to a clean energy future.

To determine if a SunPower SunVault or Tesla Powerwall home battery is right for your home energy needs, our certified Solar Technologies representatives can answer all your questions. If you’re ready to change the way you power your home and start saving more with solar, contact us today for a free customized quote.

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