Energy storage technologies, store energy either as electricity or heat/cold, so it can be used at a later time. With the growth in electric vehicle sales, battery storage costs have fallen rapidly due to economies of scale and technology improvements. With the falling costs of solar PV and wind power technologies, the focus is increasingly moving to the next stage of the energy transition and an energy systems approach, where energy storage can help integrate higher shares of solar and wind power.
Energy storage technologies can provide a range of services to help integrate solar and wind, from storing electricity for use in evenings, to providing grid-stability services.
Wider deployment and the commercialisation of new battery storage technologies has led to rapid cost reductions, notably for lithium-ion batteries, but also for high-temperature sodium-sulphur (“NAS”) and so-called “flow” batteries. Small-scale lithium-ion residential battery systems in the German market suggest that between 2014 and 2020, battery energy storage systems (BESS) prices fell by 71%, to USD 776/kWh. With their rapid cost declines, the role of BESS for stationary and transport applications is gaining prominence, but other technologies exist, including pumped hydro, flywheels, and thermal energy stores.
IRENA is tracking the current costs and performance of BESS and is monitoring how the value of these systems in different applications and international markets is likely to evolve over time with increasing self-consumption of rooftop solar PV, the provision of grid services such as frequency regulation or ramping needs, as well as peak power demand shaving in industry and alike.
Written by
Kristen Cramer
April 5, 2023
Fact-checked by
Tom Grupa
A solar battery costs $8,000 to $16,000 installed on average before tax credits. Solar battery prices are $6,000 to $13,000+ for the unit alone, depending on the capacity, type, and brand. A home solar battery storage system connects to solar panels to store energy and provide backup power in an outage.
Solar battery total installed cost by home size (before tax credit) - ChartSolar battery cost Home size (SF) System size Average cost installed (before tax credit) Average cost installed (after tax credit)* < 1,000 SF 5 kWh $5,300 – $13,000 $3,700 – $9,100 1,000 – 1,500 SF 10 kWh $9,000 – $20,000 $6,300 – $14,000 1,500 – 2,000 SF 15 kWh $10,000 – $23,000 $7,000 – $16,100 > 2,000 SF 20 kWh $13,500 – $26,000 $9,500 – $18,200*Based on a 30% federal tax credit if installed by December 31, 2032.
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Solar battery prices are $6,000 to $13,000 on average or $600 to $1,000 per kWh for the unit alone, depending on the capacity, type, and brand. Batteries with more than 25 kWh capacity for whole-house backup can exceed $25,000, not including installation.
Solar battery prices System size / capacity Unit price (battery only) 3 kWh – 4 kWh $3,000 – $5,000 5 kWh – 7 kWh $3,300 – $10,000 8 kWh – 11 kWh $7,000 – $17,000 12 kWh – 17 kWh $8,000 – $20,000 18 kWh – 25 kWh $11,500 – $23,000 > 25 kWh $17,500 – $40,000+The following factors impact the cost of a solar battery:
Energy capacity (kWh) – Energy capacity is the amount of power the battery can store and is the biggest factor in the battery's price. Larger capacity batteries cost more but can power more appliances or provide backup power for a longer period of time.
Power output – The power output indicates how much power (kW) the battery can deliver all at once. The higher the power output, the more devices and appliances it can power at the same time.
Peak power is the amount of energy the battery can provide for a short time to handle the initial surge required by most large appliances.
Continuous power is the amount of energy the battery can steadily supply.
Round-trip efficiency – Round-trip efficiency is the percentage of energy stored in the battery that may be retrieved later. The higher the battery's round-trip efficiency, the less energy is lost in the storage and transfer process.
Depth of Discharge (DoD) – The Depth of Discharge is the maximum percentage of the battery that can be discharged relative to its total capacity before recharging is recommended. Look for a battery with a maximum DoD of 90% or more.
Battery chemistry – The two most commonly used battery types for residential use are lithium iron phosphate and nickel manganese cobalt, both based on lithium-ion chemistry. Lead-acid batteries are a cheaper but less efficient alternative.
Lithium iron phosphate (LFP) – LFP batteries have a longer lifespan, are safer and more efficient, and use less-toxic materials than NMC batteries, making them easier to recycle. However, they have a higher upfront cost.
Nickel manganese cobalt (NMC) – NMC batteries have a lower upfront cost, can better withstand colder temperatures, and have a high energy density—the ability to store a large amount of energy while taking up less space. However, they have a shorter lifespan and aren't as safe as LFP batteries.
Lead-acid – Lead-acid batteries have been on the market the longest and are cheaper than LFP or NMC batteries but are less efficient, have a lower capacity and short lifespan, and require more frequent maintenance.
AC vs. DC batteries:
Alternating current (AC) batteries cost more but can be used with any solar panel system, are easier to install when retrofitting an existing solar panel system, and can be charged from solar panels or the grid. However, AC systems are less efficient.
Direct current (DC) batteries cost less and are more efficient but are more complicated to install, increasing installation costs.
*Not including installation.
Look for these key details when evaluating a solar battery warranty:
End-of-warranty capacity – Manufacturer warranties often guarantee the battery will retain 60% to 70% of its original capacity at the end of the warranty period.
Guaranteed cycle life – Some manufacturers guarantee the battery's performance for a maximum number of usage cycles. One cycle occurs when the battery is discharged fully to its stated Depth of Discharge.
A Tesla Powerwall costs $11,500 installed for the first unit and $7,000 for each additional unit installed at the same time. The Powerwall works with most solar panel or solar roof systems. Most homes need 2 or more Powerwalls to supply whole-house backup power for one day.
Tesla Powerwall installationA Generac PWRcell costs $12,000 to $20,000 installed on average, depending on the system size. The PWRcell—pronounced "power cell"—can be configured for 9, 12, 15, or 18 kWh per battery cabinet. Two cabinets can connect to a single inverter for up to 36 kWh total backup power.
Whole-house solar battery backup costs $20,000 to $32,000 installed, not including solar panels. The average home uses 28 to 30 kWh per day, requiring batteries with at least that total capacity or more to power the entire home for one day.
Without a solar battery, grid-tied solar panel systems cannot power a house during an outage because by law they must turn off when the grid goes down. This safety measure protects utility workers from electrocution by blocking your system from sending power into the grid while workers are repairing the lines.
A Generac PWRcell battery in a home garage.The cost to install solar panels and a battery is $16,200 to $37,700 after the 30% federal tax credit. Solar battery installation is cheapest and easiest when installing the battery at the same time as a solar panel or solar roof system to minimize labor and permitting costs.
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Solar panels cost $10,600 to $26,500 installed on average after the tax credit.
A solar roof costs $29,400 to $56,000 installed after the tax credit. Most solar roof installations include one battery.
A Tesla solar roof costs $42,000 to $105,000 installed after the tax credit and includes one or more Tesla Powerwalls, depending on the system size.
*Before subtracting 30% tax credit.
Other factors also affect the installation cost:
Number of batteries – Upfront costs are cheaper when powering only essential appliances with a single battery during a short-term outage. Whole-house or all-day backup typically requires two or more batteries, increasing costs.
See also:Compatibility – Before purchasing a solar battery, confirm it is compatible with your solar panel system. Many batteries require an inverter for compatibility.
Labor type – Many solar battery manufacturers do not offer installation services directly and instead partner with local solar installers or require homeowners to hire a separate installer.
Inverter – Some batteries come with a built-in inverter, while others require a separate inverter. Installing an external inverter increases labor and equipment costs.
Most inverters have a maximum power output rating, which limits the amount of power the home can draw from the battery at any given time. When installing multiple batteries to power more appliances and devices, confirm the inverter can handle the combined output of all the batteries.
Labor to install a solar battery costs $2,000 to $3,000 on average. Labor costs are lowest when installing a battery at the same time as a solar panel system. Retrofitting an existing system to add a new battery can increase labor costs by 30% to 50%.
Solar battery installation may require additional electrical work:
Electricians cost $50 to $130 per hour.
Running new electrical wiring costs $7 to $10 per linear foot.
Replacing an electrical panel costs $1,300 to $4,000, depending on the amps. Installing a sub-panel costs $500 to $1,000.
A critical load panel costs $1,000 to $2,000 when installed with a solar battery. Most solar batteries do not have enough power to back up a whole home but instead power only essential circuits. A backup load panel ensures critical lights and appliances stay powered during an outage.
Solar batteries are eligible for the 30% Residential Clean Energy Credit until 2032. This federal tax credit—formerly known as the Solar Investment Tax Credit (ITC)—decreases to 26% for installations in 2033 and 22% in 2034.
Check the Database of State Incentives for Renewables & Efficiency® to find additional rebates and local tax credits available in your state.
Purchased or loan-financed systems qualify for the federal tax credit but leased systems do not.
Solar battery storage systems are expensive but may be worth it for homeowners living in areas that experience frequent power outages or where net metering isn't offered. Solar batteries are also ideal if you are seeking a fully off-grid system.
For homeowners eligible for net metering, the benefits of a solar battery typically don't outweigh the high cost. Net metering allows you to sell surplus energy from your solar panels back to the grid for a credit toward your electrical bill instead of storing the excess energy in a battery.
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The cheapest solar battery is a flooded lead-acid battery. However, lead-acid batteries have a short lifespan of only 3 to 5 years, require regular maintenance and winterizing, and are more suited to hands-on homeowners building their own fully off-grid systems.
Solar batteries are expensive due to the rising material costs for lithium and cobalt. Other components— including an inverter, monitor, and cooling system—add to the cost. Most manufacturers also provide software to monitor the battery's usage and status, increasing development costs.
The number of solar batteries you need depends on the household size, energy consumption, climate, and whether you want backup power for short-term outages or total grid independence. The average home needs 2 or more 10 kWh batteries to supply whole-house backup power for one day.
Homeowners seeking an off-grid solar-powered system need a total battery storage capacity of 25 to 30 kWh to handle essential loads and power appliances like an electric range, washer/dryer, water heater, and central A/C.
Solar batteries last 3 to 15 years, depending on the type. Lead-acid batteries have the shortest lifespan at 3 to 5 years, while lithium-ion solar batteries last 10 to 15 years. Most manufacturer warranties guaranty the battery will retain 60% to 70% of its original capacity at 10 years.
A 13 kWh solar battery can power a house for 4 to 12 hours, depending on the number of lights and appliances running. An average family of four will require a minimum of 25 kWh to power LED lights, major appliances, and air conditioning or a heat pump for one day.
Before hiring a solar installer near you, be sure to:
Get at least three in-person estimates to compare.
Look for contractors who are members of the Solar Energy Industries Association (SEIA) or certified by the North American Board of Certified Energy Practitioners (NABCEP).
Browse their reviews on HomeGuide and Google.
Choose a company that is licensed, insured, bonded, and has been in business 5+ years.
Discuss your electricity usage and power requirements with the installer to ensure your system is sized correctly.
Get a detailed estimate, contract, and warranty in writing before the work begins.
Never pay in full before the project starts. Follow a payment plan instead.
How long have you been in business?
What solar certifications do you have?
How many solar batteries have you installed in the past year?
Do you have any references I can contact?
How many solar batteries do I need to power my home, and what size should I get?
Can I use my solar battery to go off-grid?
How long will it take the battery to charge?
Where do you recommend mounting the battery in my home?
Do I need a backup load panel, inverter, or other equipment?
Does the estimate include all required electrical work?
What other costs should I expect?
How long will the installation take?
Will the installation require a permit, and if so, will you obtain it?
Will you assist me in claiming any rebates and incentives?
What does the warranty include?
Who should I contact for troubleshooting or repairs?
Do you offer financing?
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