Solar energy storage systems (solar batteries) capture excess energy during the sunniest times of the day. This power is then stored in the battery and ready for use at night when the solar panels aren’t producing energy. Batteries also provide backup power for grid-tied solar systems during power outages.
Although solar panels provide clean energy and help reduce energy costs, they have two shortcomings: they only generate power when the sun is shining, and they can’t store excess energy on their own.
Solar energy storage technologies solve this problem and enhance the efficiency of solar systems. Solar batteries capture solar panel-generated electricity, store it, and release it when needed.
Solar energy storage involves gathering excess energy from a solar panel system and storing it in another form for later use.
Solar panels generate maximum energy during peak sunlight hours. With a solar energy storage system, you don’t have to use all the electricity your solar array produces. The storage devices save surplus solar energy in chemical, thermal, or kinetic form and then release it when there’s peak demand.
Therefore, a solar-plus-storage system is more efficient as it balances power supply with demand.
You only NEED an energy storage system for an off-grid solar system. For all other applications, it’s a nice-to-have that will boost your system’s performance and give you greater energy independence.
Most homeowners and businesses that install solar energy systems have their solar panels tied to the electric grid. This allows them to still draw electricity when their solar panels aren’t working (i.e. night time or periods of little sun). Being grid-tied also enables you to send excess generated power back to the utility company to earn credits and lower your electric bill (net metering billing).
But grid-tied systems present some challenges for solar system owners:
Those are the two primary reasons most people invest in a solar battery system.
Other reasons to consider a solar energy storage system include:
Solar energy storage solutions fall into different categories depending on what form of energy they store.
Batteries energy storage systems (BESS) are the most practical solar energy storage solutions for homeowners. They’re rechargeable solar batteries that capture solar energy and store it in chemical form.
So when your solar panels absorb sunlight, the batteries convert the DC (direct current) energy to AC (alternating current) and bank it for later use.
Here are the main types of solar batteries:
Pumped hydro energy storage (PHES) involves two-reservoir systems installed along power grid transmission lines. PHES systems comprise the largest percentage (about 93%) of utility-scale energy storage in the US. They store and release renewable energy by pumping water in and out of the reservoirs, depending on the energy supply and demand.
When there’s excess solar energy, the PHES system uses it to power turbines that pump water into the higher reservoir. Then, when supply drops and demand increases, the system releases water back into the lower reservoir, generating kinetic energy.
PHES is an inexpensive and efficient way of storing solar energy. But setting it up requires ample space, regulatory permits, and a complex process. It’s generally only used in commercial applications, but may be suitable for large off-grid systems that power a homeowner’s farm.
Thermal storage systems (TSS) store surplus solar power in insulated tanks using fluid like molten salt or solid matter. TSS systems are practical storage solutions for companies because:
However, installing TSS systems can be expensive since the systems require plenty of space.
Flywheels have large rotor blades that spin in a vacuum, producing a force that powers turbines. This storage system stores excess power in the form of kinetic energy and turns it back to electricity upon demand.
FES systems are more efficient and have faster response rates than solar battery storage systems. But their installation requires higher upfront costs and a bigger space.
These systems use excess energy to compress and store air in underground tanks (caverns). CAES systems release the compressed air upon demand, using it to power turbines and produce electricity.
They have higher efficiency and reduce carbon emissions by minimizing the use of natural gas. CAES systems are also durable and have a high storage capacity. On the downside, they require specific underground locations to set up, so they are rare.
The cost of solar energy storage systems is highly dependent on several factors.
The installation cost of a solar energy storage system is calculated in dollars per kilowatt-hour ($/kWh).
The following factors determine how much you’ll spend in setting up a solar energy storage system:
Even the most ardent solar evangelists can agree on one limitation solar panels have: they only produce electricity when the sun is shining. But, peak energy use tends to come in the evenings, coinciding with decreased solar generation and causing a supply and demand issue. The thing is, solar panels often pump out more than enough energy during those lower demand hours when the sun is shining to meet peak demand later in the day. This means that efficient solar energy storage can open up a wealth of possibilities for homeowners and businesses alike.
In this blog, we’ll look at solar energy storage in-depth, its benefits, and even tools for modeling it on your solar installs.
Click above to learn more about selling solar under NEM 3.0.Storing this surplus energy is essential to getting the most out of any solar panel system, and can result in cost-savings, more efficient energy grids, and decreased fossil fuel emissions. Storing solar energy has a few main benefits:
. If electricity isn’t stored, it has to be used at the moment it’s generated. Energy storage allows surplus generation to be banked for peak-use. As far as renewable energy is concerned, storing surplus power allows the lights to stay on when the sun goes down or the wind stops blowing. Simply put, energy storage allows an energy reservoir to be charged when generation is high and demand is low, then released when generation diminishes and demand grows.
Short-term solar energy storage allows for consistent energy flow during brief disruptions in generators, such as passing clouds or routine maintenance.
The energy grid is vulnerable to disruptions and outages due to anything from wildfires to severe weather.
Solar energy storage creates a protective bubble during disruptive events by decentralizing where we get our energy from.
If you live in a state that has no solar net energy metering, or policies that don’t fairly compensate you for the solar energy you generate, battery storage can help lower your utility bills while consuming more of your own power. So, while you may not be compensated as much for excess energy sent to the grid, any additional solar power generated and stored throughout the day can be discharged from a battery at night or on cloudy days in the place of utility consumption.
Solar energy storage can be broken into three general categories: battery, thermal, and mechanical. Let’s take a quick look at each.
Batteries are by far the most common way for residential installations to store solar energy. When solar energy is pumped into a battery, a chemical reaction among the battery components stores the energy. The reaction is reversed when the battery is discharged, allowing current to exit the battery. Lithium-ion batteries are most commonly used in solar applications, and new battery technology is expanding rapidly, which promises to yield cheaper, more scalable battery storage solutions. In fact, U.S. energy storage is expected to reach nearly 7.5 GW annually by 2025, a sixfold growth from 2020, representing a market worth $7.3 billion.
Thermal energy storage uses various mediums — such as water or molten salt — to absorb and retain heat from the sun. This heated medium is stored in an insulated tank until the energy is needed, usually to boil water for energy generation.
Mechanical energy storage takes advantage of the potential energy of an object to generate electricity. Mechanical storage methods convert surplus electrical power into mechanical power, which is converted back into electricity for later use. There are three prominent mechanical energy storage systems:
This method uses surplus electricity to spin a flywheel, which later generates electricity to supply quick energy during peak demand times.
With pumped hydro, water is pumped uphill to a reservoir located above turbine generators. The water is allowed to flow through turbines and generate electricity when demand is high.
With this energy storage system, compressed air is pumped into large vessels such as a tank or underground formation. The air is released to generate electricity during peak demand.
There’s no silver bullet solution for solar energy storage. Solar energy storage solutions depend on your requirements and available resources. Let’s look at some common solar energy storage options for commercial and home applications.
Utility companies and other businesses generally have bigger budgets than individual households, making mechanical and thermal storage viable options. Though costs for these storage methods can be high, they help utilities keep up with peak energy demand.
deployed
476 MW of new storage, a 240% increase from the record-breaking previous quarter. Most of the new deployments are one-hour front-of-the-meter (FTM) storage solutions, but nonetheless offer a promising look into the future of commercial solar energy storage.
. The most
recent government estimates calculate compressed air
costs at $105/kWh, making it the most cost-effective mechanical storage option for large-scale applications.
Surplus solar energy can be used to pump water uphill, creating a massive amount of potential energy.
Current pumped hydro costs
are around $165/kWh, making it the second-best option for mechanical energy storage at scale. It’s only available in certain areas, however, as new pumped hydro involves high upfront costs and significant regulatory hurdles.
Residential solar has myriad benefits, including resiliency, cost savings, and decentralization of electrical production (otherwise known as “virtual power plants”). But the commercial energy storage methods we discussed above are likely cost-prohibitive for the average homeowner. Thankfully, battery storage can now offer homeowners a cost-effective and efficient way to store solar energy.
Lithium-ion batteries are the go-to for home solar energy storage. They’re relatively cheap (and getting cheaper), low profile, and suited for a range of needs. Other batteries commonly available for residential use include saltwater batteries and lead-acid batteries.
Regardless of the battery type, home backup batteries allow homeowners to save energy during high production, low demand times (i.e. during the workday) for use during high demand periods when generation diminishes. Home solar energy storage inherits the same benefits of large-scale solar energy storage, translating into resiliency, uninterrupted energy, and cost savings. And these benefits go directly to the homeowner.
Technology to help design solar battery storage
Designing a storage system along with a solar installation used to be labor-intensive and include a fair amount of guesswork. Now, software like Aurora‘s includes battery storage as part of its offerings.
Using Aurora Solar’s Battery Storage Tool, solar installers can analyze load off-set, calculate the projected price of a project, forecast smart battery sizing recommendations based on customer priorities, and present it to the customer in a compelling, easy-to-understand way.
Aurora has also introduced battery self-consumption modeling. You can learn more here.
So, while the technology used to store solar energy may seem complicated or overwhelming to some customers, Aurora can help you break down the complexities for customers with interactive and easy-to-understand models of performance and savings.
Click above to learn more about modeling battery storage for self consumption in Aurora.Click here to learn more about Aurora’s battery self-consumption modeling capabilities.
The sun offers a limitless supply of clean power, but harnessing it can be a challenge. Thankfully, several options for commercial and residential storage offer proven solutions for storing solar energy, and emerging technologies are being developed daily. For commercial applications, mechanical storage options provide effective solutions to harnessing solar energy when it’s needed most, and grid-scale battery storage will likely become available soon. For residential solar, battery storage is the best option, with a variety of affordable units on the market. Together, these solutions provide an effective portfolio for storing solar energy and provide a compelling argument for further solar deployment in commercial and residential settings.
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To see battery self-consumption modeling in action, schedule a quick demo.
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