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Illinois Solar Battery Storage Market at a Glance

Illinois solar battery storage

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Illinois is a Midwestern state in the US with beautiful landscapes, forests, rolling hills, wetlands, and farmlands, and these are the reasons it got the name “The Prairie State.” Most importantly, it is a state full of sunshine, making Illinois a thriving solar energy market. 

Illinois has already made its mark in the solar industry and encouraging residential and commercial property owners with a wide range of solar incentives. Starting with a strong net metering policy and RPS to a property tax break, Illinois has proved to be a strong place for generating solar power.

Home and commercial property owners can customize their solar panels, batteries, racking systems, and inverters, along with the installation’s general aesthetic aspects. This scope of customization has made solar consumers realize these various factors. For instance, premium solar panels are available with high efficiencies and warranties but are likely to be more costly. 

Depending on the energy requirement, homeowners can choose the size of a solar system with high-efficiency that can generate more energy. Besides, consumers can determine which solar warranties are most suitable for their requirements. These are a few factors to consider when choosing a solar panel system.

Solar Battery/Installation Costs in Illinois

The cost of solar energy systems will vary whether you buy only the solar or solar-plus-battery systems for energy storage. 

Before you decide whether installing a solar battery is a good idea or not, you need to learn about the price. Like the solar panel system, consider the costs as a gross price and a price per applicable capacity.

Solar battery costs are between $5,000 and $7,000, and from $400 per kWh to $750 per kWh. Remember that these costs are only for the battery and do not include installation or additional essential equipment. The average price of installing a solar battery is between $11,000 and $18,000, and $800 per kWh to $1,300 per kWh.

Solar battery systems for residential properties are a relatively new technology. Similar to solar panels, the cost of solar batteries primarily depends on their manufacturing materials and the power capacity they can provide. The installation cost will go up if a battery can operate off-grid than installing a battery that runs after connecting to the power grid.

The price of a couple of leading solar battery costs may give you a fair idea. According to the estimate by EnergySage, the list price of Tesla Powerwall is $6,500. You also have to buy the Gateway and pay for installation, which adds $7,600 plus to the total cost of a single Powerwall. It means the cost of installation will be between $9,600 and $15,600.

Another brand LG Chem’s RESU 10H battery will typically cost between $9,500 and $13,000 for installing a full system.

It is important to keep in mind that list prices for solar batteries are just one aspect. Unless your solar battery has a built-in inverter, you need to install a specialized inverter to manage electricity flow through the battery. When pairing up a solar battery with solar panels, you only need to install one inverter. You need to get your solar batteries installed by a licensed electrician.

Currently, the price of the solar-plus-battery system is relatively lower due to the federal investment tax credit, which is one of the most impactful and reliable incentives for solar in the US. The ITC allows potential solar buyers to get a 26 percent deduction from the federal taxes for the total system cost. For instance, if a solar-plus energy system’s installation cost is $15,000, it will be eligible for a tax deduction of $3,900.

The 26 percent federal tax credit will stay only until the end of 2020, as in 2021, the percentage of the tax credit will be down to 22 percent. It means consumers have to pay higher prices for a solar-plus-battery system. However, commercial solar buyers will still get a 10 percent deduction from their taxes for a commercial solar system in 2022 and beyond.

Illinois Looks to Expand its Battery Storage Market to Manage a Surge of Solar Energy Consumption

The energy storage market has played a crucial role in Illinois for the rapid growth of the solar energy market. Illinois has an ambitious goal regarding renewable energy, and according to it, the energy sources in the state must produce 25 percent of overall electricity through renewable energy by 2025. 

Besides utility, Illinois has also been prioritizing and valuing energy storage. The state government is considering rolling out more incentives and urging developers to make the battery storage system more affordable and efficient.

Currently, Illinois has limited storage capacity. According to the “Illinois Coal to Solar and Energy Storage Act” of 2020, the state’s current energy storage capacity is 130 MW. This is a similar figure to several US states; however, like New York and California, Illinois needs to have a long-term strategy that will significantly increase its storage capacity.

The Future Energy Jobs Act in Illinois focuses on generating renewable energy through solar and wind. The new state legislation aims to increase energy production and move the state toward 100 percent renewable energy by 2050. This potential expansion will require increasing solar storage capacity to save the extra energy for use when production is low.

Currently, the state has five pilot projects for energy storage, either live or in the planning phase. These pilot projects have an aim to install a 25-kilowatt energy storage system in Beecher. 

Besides, a 2.43-megawatt solar energy project is underway in Zion. The project will have nearly 5,000 solar panels, which will provide electricity to around 500 homes. The energy storage plant in Zion will cost nearly 50 percent less than the cost to upgrade the existing facility through traditional technologies.

It will still take some time for solar technologies to be economical. Bloomberg’s report shows that the cost of generating electricity through the duration of an energy project (Levelized cost) for lithium-ion batteries is $187 per megawatt-hour. 

According to many energy experts, the cost is one of the main factors preventing the large-scale deployment of solar energy. Although prices for storage solutions have dropped in recent years, there are still many ways to make it affordable. 

Experts further state that they expect the technology to evolve and go beyond lithium-ion batteries to more efficient and environment-friendly options. For example, flow batteries have a faster charge time and can last longer, in terms of charge and duration. Another option is flywheel storage. These options could be cost-effective and efficient for utility-scale projects. However, for residential consumers, lithium-ion batteries remain the most economical option.

Energy policies are another crucial piece. Besides long-term energy implementation strategies, other US states have incentive programs for energy storage. Some state commissions have already rolled out guidelines for utilities to make storage as part of their integrated resource plans. Illinois is yet to reach there, even though the state is well-positioned to initiate such programs with proactive decision-making. 

The state would require some collaboration between solar and energy storage plans. The federal and state incentive programs often focus on developing solar energy, but an extension of solar-plus-storage would be a good idea. It is because solar-plus-storage is more valuable than solar alone. Having solar and the battery system tied together at the regulatory level is likely to spur energy storage development. It will lower prices further and create a market for the technology.

How to Choose the Best Battery for a Solar Energy System

There are certain specifications that consumers can consider when checking out solar battery options, including the durability of the battery or how much power the system can provide. We have listed the key factors below that you should consider while buying a solar battery system. 

If you consider solar-plus-storage options, you may find many detailed product specifications. The most important factors during your evaluation should be the battery capacity, power ratings, round-trip efficiency, depth of discharge (DoD), battery life & warranty, and manufacturer. 

Capacity and Power

A solar battery system’s capacity refers to the total electricity it can store, measured in terms of kilowatt-hours (kWh). Most residential solar batteries are generally “stackable,” which means you can use multiple batteries with your solar-plus-battery storage to get extra capacity. 

Although the capacity indicates the battery’s size, it does not tell you the amount of electricity it can produce at a given moment. To learn about all the aspects of your solar battery system, you also need to consider the battery’s power rating. Power ratings are crucial in solar batteries, as it refers to how much electricity a battery can generate at one time. 

Solar battery storage with a high capacity but a low power rating will generate a low amount of electricity (to run a few major appliances) for an extended period. On the other hand, a battery that comes with low capacity and a high power-rating can provide electricity to your entire home, but for a limited time.  

Round-trip Efficiency

The round-trip efficiency of a battery is about the amount of energy you can use as a percentage of the total energy it took to store. For example, if your solar battery can store 5 kWh of electricity, only 4 kWh of useful electricity will be available. It means the battery is providing a round-trip efficiency of 80 percent (4-kilowatt-hour ÷ 5 kilowatt-hours). Generally, a higher round-trip efficiency indicates that your solar batteries provide more economic value. 

Depth of Discharge (DoD)

Most solar battery storage systems require keeping some charge all the time because of their chemical composition. If you use all of the battery’s charge, its lifespan will significantly shorten. 

The depth of discharge (DoD) of a solar battery refers to how much of the total battery capacity you have used. Most manufacturers mention in the products a maximum DoD for optimal battery performance. For example, if you have a 10 kWh battery with a DoD of 90 percent, you should not ideally use more than 9 kWh of the capacity before recharging. Usually, a higher DoD means you can use more of your battery’s capacity. 

Battery life & warranty

While using solar battery storage, the batteries will charge and drain daily. Over time, the battery’s capacity to hold a charge will decrease with more usage. For example, a solar battery may have the warranty to run 5,000 cycles or 10-15 years at 70 percent of its actual capacity. It means when the warranty ends, the batteries will not lose more than 30 percent of its original capacity to store energy.  


Many companies in Illinois manufacture solar battery systems in various designs and sizes. You can buy batteries from a company with a long history of doing business in the solar energy storage market with steady technology. You may also purchase batteries from a tech startup that offers a brand-new technology but has less history. It all depends on your priorities. No matter whom you buy from, it is essential to evaluate the warranties that come with each product as a crucial factor while making your decision.

What are the Best Types of Solar Batteries?

Typically, solar batteries for home energy storage come with lithium-ion, saltwater, and lead-acid. Generally, lithium-ion batteries are the best and most popular option for a solar system, though other batteries are more affordable. 

Lithium-ion Battery

Most solar battery systems have some lithium-ion chemical composition. Lithium-ion batteries are lightweight and more compact. These batteries also come with a longer lifecycle and higher DoD. However, lithium-ion batteries are relatively more expensive than other types of batteries. 

Lead Acid Battery

Lead-acid batteries have been in use in off-grid solar energy systems for many years. Although these batteries have a relatively short lifespan and lower DoD compared with other battery types, they are currently the least expensive options on the energy storage market. For homeowners, who want to opt for off-grid and need to store plenty of energy, lead-acid batteries are a good option.

Saltwater Battery

Saltwater water batteries are new entrants in the energy storage industry. Unlike other battery storage options, these batteries do not have heavy metals and instead rely on saltwater electrolytes. Besides, you can easily recycle a saltwater battery. However, these batteries are still relatively untested. 


The growth of the energy storage or battery system market has put Illinois on the path of accelerated growth in terms of achieving the state’s long-term energy-efficiency goals. Leading solar installation and energy storage companies are doing their bit by streamlining the solar energy distribution process and equipment to provide uninterrupted power supply to Illinois consumers. 


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