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Storing Solar Energy: What You Need to Know

solar panels on roof

Solar panels are one of the best options for a natural and alternative energy source. They are an excellent way to reduce your carbon footprint, lower your energy bills, and free yourself from depending on energy companies.

Solar panels do have one limitation, however: they only produce electricity when the sun is shining. That’s a pretty big issue when peak energy usage is during the evening hours when the sun is setting.

The good news is, solar panels usually generate more than enough energy during the lower-demand hours when the sun is shining to meet the demand that happens later in the day. That’s where solar energy storage comes in. Combining solar panel systems with solar energy storage makes it possible to use solar energy, even when there’s no sun. Energy storage saves the electricity generated during the day for later use.

In this blog, we’ll take a thorough look at solar energy storage, including how it works, what the benefits are, and the best ways to store solar energy.

How is Solar Energy Stored?

Solar energy storage can be grouped into three main categories: battery, thermal, and mechanical.

Solar Battery Energy Storage

By far the most commonly known, battery energy storage is the most often used storage option in residential solar power systems.

When solar panel energy is driven into a battery, it causes a chemical reaction, and energy is stored. When a battery is discharged, that chemical reaction is reversed, which creates voltage between two electrical contacts, causing current to flow out of the battery. Lithium-ion batteries are the most common type of battery used in solar, though new battery technology is growing quickly.

Thermal Energy Storage

Thermal energy storage is a technology which uses a fluid, such as water or molten salt, or other materials to absorb and retain heat from the sun. This heated medium is then stored in an insulated tank until the energy stored is needed. The heat is then used to boil water. The resulting steam drives a turbine and produces electrical power.

Mechanical Energy Storage

Mechanical energy storage uses the potential energy of an object to generate electricity. Mechanical storage methods convert excess electrical power into mechanical power, which is then converted back into electricity for later use. There are three primary mechanical energy storage systems:


A flywheel is a heavy wheel attached to a rotating shaft. This method uses excess electricity to spin the flywheel. This energy can be extracted by attaching the wheel to an electrical generator, which uses electromagnetism to slow the wheel down and produce electricity. Although flywheels can quickly provide power, they can’t store a lot of energy.

Pumped hydro

Pumped-storage hydropower is an energy storage technology based on water. Electrical energy is used to pump water uphill to a reservoir located above turbine generators. Later, the water can be allowed to flow back downhill and turn the generators to create electricity when demand is high.

Pumped hydro is a well-tested storage technology that has been used in the United States since 1929. However, it needs suitable landscapes and reservoirs to be truly functional. These can be natural lakes or man-made by constructing dams, but they require lengthy regulatory permits, long implementation times, and large initial capital.

Compressed air

With this energy storage system, compressed air is pumped into large vessels such as a tank or natural underground formations, like caves. A compressor system pumps the vessels full of pressurized air. The air is released and used to drive a turbine that produces electricity during peak demand.

Later we will discuss which power storage systems are used in residential versus commercial solar, and which might work best for you. First, however, let’s look at the benefits of having solar storage.

What are the Benefits of Solar Storage?

Storing solar panel energy is crucial to getting the most out of any solar panel system, and can result in more efficient energy usage, cost-savings, reduced power outages, and decreased fossil fuel emissions. Storing solar energy has many benefits including:

Balancing Electrical Loads

Without storage, electricity must be generated and used at the same time. Energy storage allows excess energy to be kept for when it’s needed. Where renewable energy is concerned, storing excess power keeps the lights on when the sun goes down. It allows an energy reserve to be charged when generation is high and demand is low, then released when generation is low and demand is high.

Maintaining Backup Power

Outages and disruptions happen. Be it from a flood, fires, severe weather, accidents, or any other disruptive event. With solar energy storage, you create a backup during outages and disruptions by decentralizing where you get your energy from.

Eliminating Power Gaps

If you’re using a solar power energy system exclusively, without storing any surplus power, you are vulnerable to gaps in power availability. Short-term solar energy storage creates consistent energy flow during any brief disruptions in generators, such as passing clouds or routine maintenance.

Increasing Savings from Energy Use

Solar storage can help lower your utility bills while consuming more of your own power. Excess solar power generated and stored throughout the day can be used via a battery at night or on cloudy days in the place of using your utilities, which saves you money.

Reducing Your Carbon Footprint

Though California is second only to Texas in the combined total electricity generation from all renewable resources, and leads the nation in generation from solar power, geothermal, and biomass energy, many utility companies still create most of their power using fossil fuels.

With solar power storage, however, you use almost all of the electricity your solar energy system produces which reduces your use of fossil fuel generated power. Optimizing the use of renewable energy that your home runs on cuts back on carbon emissions and makes for a happier and healthier planet.

The Best Way to Store Solar Energy

There’s not a singular perfect solution for solar energy storage. The best solution for you depends on your requirements and available resources. Each setup is different which means there’s not a one size fits all solar storage answer. Here are some common solar energy storage options for both home and commercial use.

Storing Solar Energy At Home

Technically, homeowners can store solar energy through mechanical or thermal energy storage, but these options require a lot of space, materials, and moving parts. They may not be the most practical way to store energy for a home.

Most homeowners choose to store their solar energy by using battery storage. Lithium-ion batteries are the most common choice. They’re relatively cheap, low profile, and well-suited for a fairly wide range of needs. Other battery options for residential use include saltwater batteries and lead-acid batteries.

No matter the battery type, home backup solar batteries give homeowners the opportunity to save energy during high output, low-use times for use during high consumption periods when output is low. Home solar energy storage maintains the same benefits of large-scale solar energy storage, which means cost savings and uninterrupted energy.

The best part? The benefits go directly to the homeowner.

Commercial Solar Storage

Utility companies and other businesses have bigger budgets and more resources than individual households. This makes mechanical and thermal storage more viable options. Though initial costs for these storage methods may be high, they help keep up with high energy demand and reduce the long-term cost of utilities.

Each company must thoroughly examine the costs versus benefits, and the resources and land available before choosing the option that works best for their solar storage needs.

Is Solar Energy Storage for You?

Solar storage allows homeowners and businesses to maximize the use of their solar output while creating many benefits. They lower overall utility costs, fill any gaps in solar generated power, create a backup solution for outages, and reduce your carbon footprint. There are several options available that can be chosen to fit your needs and create the greatest benefit for your setup.

Are you ready to implement your own solar power storage system? Do you have more questions? Let us help! Work with true experts in solar energy storage by giving us a call.