Abattery energy storage system (BESS),battery storage power station,battery energy grid storage (BEGS) orbattery grid storage is a type ofenergy storage technology that uses a group ofbatteries in the grid to storeelectrical energy. Battery storage is the fastest respondingdispatchable source of power onelectric grids, and it is used to stabilise those grids, as battery storage can transition from standby to full power in under a second to deal withgrid contingencies.^[1]

Battery energy storage systems are generally designed to deliver their full rated power for durations ranging from 1 to 4 hours, with emerging technologies extending this to longer durations to meet evolving grid demands.^[2] Battery storage can be used for short-termpeak power^[3] demand and forancillary services, such as providingoperating reserve andfrequency control to minimize the chance ofpower outages. They are often installed at, or close to, other active or disused power stations and may share the same grid connection to reduce costs. Since battery storage plants require no deliveries of fuel, are compact compared to generating stations and have no chimneys or large cooling systems, they can be rapidly installed and placed if necessary within urban areas, close to customer load, or even inside customer premises.A Battery Energy Storage System (BESS) from 1 kW to 1 MW stores electricity for use during peak demand or power outages, ensuring reliable energy supply. Using advanced lithium battery technology, it supports solar integration, reduces electricity costs, and provides fast, efficient backup power for homes, businesses, and industrial applications.

As of 2021, the power and capacity of the largest individual battery storage system is anorder of magnitude less than that of the largestpumped-storage power plants, the most common form ofgrid energy storage. For example, theBath County Pumped Storage Station, the second largest in the world, can store 24 GWh of electricity and dispatch 3 GW while the first phase ofVistra Energy's Moss Landing Energy Storage Facility can store 1.2 GWh and dispatch 300 MW.^[4] However, grid batteries do not have to be large — a high number of smaller ones (often ashybrid power) can be widely deployed across a grid for greater redundancy and large overall capacity. By 2025, global power capacity was 267 GW with 610 GWh energy capacity.^[5]

As of 2019, battery power storage is typically cheaper thanopen cycle gas turbine power for use up to two hours, and there was around 365 GWh of battery storage deployed worldwide, growing rapidly.^[6]Levelized cost of storage (LCOS) has fallen rapidly. From 2014 to 2024, cost halving time was 4.1 years.^[7] The price was US$150 per MWh in 2020,^[8][9][10] and further reduced to US$117 by 2023.^[11]

Battery storage power plants anduninterruptible power supplies (UPS) are comparable in technology and function. However, battery storage power plants are larger.

For safety and security, the actual batteries are housed in their own structures, like warehouses or containers. As with a UPS, one concern is that electrochemical energy is stored or emitted in the form ofdirect current (DC), while electric power networks are usually operated withalternating current (AC). For this reason, additionalinverters are needed to connect the battery storage power plants to the high voltage network. This kind of power electronics includegate turn-off thyristor, commonly used inhigh-voltage direct current (HVDC) transmission.

Various accumulator systems may be used depending on the power-to-energy ratio, the expected lifetime and the costs. In the 1980s, lead-acid batteries were used for the first battery-storage power plants. During the next few decades, nickel–cadmium and sodium–sulfur batteries were increasingly used.^[14] Since 2010, more and more utility-scale battery storage plants rely on lithium-ion batteries, as a result of the fast decrease in the cost of this technology, caused by the electric automotive industry.Lithium-ion batteries are mainly used. A 4-hourflowvanadium redox battery at 175 MW / 700 MWh opened in 2024.^[15]Lead-acid batteries are still used in small budget applications.^[16]

Most of the BESS systems are composed of securely sealedbattery packs, which are electronically monitored and replaced once their performance falls below a given threshold. Batteries suffer from cycle ageing, or deterioration caused by charge–discharge cycles. This deterioration is generally higher athigh charging rates and higherdepth of discharge. This aging causes a loss of performance (capacity or voltage decrease), overheating, and may eventually lead to critical failure (electrolyte leaks, fire, explosion). Sometimes battery storage power stations are built withflywheel storage power systems in order to conserve battery power.^[17] Flywheels may handle rapid fluctuations better than older battery plants.^[18]

BESSwarranties typically include lifetime limits on energy throughput, expressed as number of charge–discharge cycles.^[19]

Lead-acid batteries, as a first-generation technology, are generally used in older BESS systems.^[20] Some examples are 1.6 MW peak, 1.0 MW continuous battery was commissioned in 1997.^[21] Compared to modern rechargeable batteries, lead-acid batteries have relatively lowenergy density. Despite this, they are able to supply highsurge currents. However, non-sealedlead-acid batteries produce hydrogen and oxygen from the aqueous electrolyte when overcharged. The water has to be refilled regularly to avoid damage to the battery; and, the inflammable gases have to be vented out to avoid explosion risks. However, this maintenance has a cost, and recent batteries such asLi-ion batteries do not have such an issue.

Lithium-ion batteries offer a long lifespan with minimal maintenance, high energy density, and lowself-discharge,^[22] which makes them ideal for modern utility-scale BESS applications.^[23]

A drawback of some types of lithium-ion batteries is fire safety, mostly ones containing cobalt.^[24] The number of BESS incidents has remained around 10–20 per year (mostly within the first 2–3 years of age), despite the large increase in number and size of BESS. Thusfailure rate has decreased. Failures occurred mostly in controls andbalance of system, while 11% occurred in cells.^[25]

Examples of BESS fire accidents include individual modules in 23 battery farms inSouth Korea in 2017 to 2019,^[26] aTesla Megapack inGeelong,^[27][28] the fire and subsequent explosion of a battery module inArizona,^[25] and the cooling liquidshort circuiting incidents and fire at theMoss Landing LG battery.^[29][30][31]

This resulted in more research in recent years for mitigation measures for fire safety.^[32]

By 2024, thelithium iron phosphate (LFP) battery has become another significant type for large storages due to the high availability of its components,longer lifetime and higher safety compared to nickel-based Li-ion chemistries.^[33] An LFP-based energy storage system that was installed inPaiyun Lodge onMt. Jade (Yushan) (the highest alpine lodge inTaiwan) and operated since 2016 without a safety incident.^[34]

Alternatively,sodium-based batteries are increasingly being considered for BESS applications. Compared to lithium-ion batteries, sodium-ion batteries have somewhat lower cost, better safety characteristics, and similar power delivery characteristics. However it has a lower energy density compared to lithium-ion batteries. Itsworking principle andcell construction are similar to those oflithium-ion battery (LIB) types, but it replaceslithium withsodium as theintercalatingion. Some sodium-based batteries can also operate safely at high temperatures (sodium–sulfur battery). Some notable sodium battery producers with high safety claims include (non-exclusive) Altris AB, SgNaPlus and Tiamat. Sodium-based batteries are not fully commercialised yet. The largest BESS utilizing sodium-ion technology started operating in 2024 in Hubei province, boasts a capacity of 50 MW / 100 MWh.^[35]

Since they do not have any mechanical parts, battery storage power plants offer extremely short control times and start times, as little as 10 ms.^[36] They can therefore help dampen the fast oscillations that occur when electrical power networks are operated close to their maximum capacity or when grids suffer anomalies. These instabilities – fluctuations with periods of as much as 30 seconds – can produce peak swings of such amplitude that they can cause regional blackouts. Some of the parameters are voltage, frequency and phase. A properly sized battery storage power plant can efficiently counteract these oscillations; therefore, applications are found primarily in those regions where electrical power systems are operated at full capacity, leading to a risk of instability.^[37] However, some batteries have insufficient control systems, failing during moderate disruptions they should have tolerated.^[38] Batteries are also commonly used forpeak shaving for periods of up to a few hours.^[3] A more recent use is strengthening transmission, as long power lines can be operated closer to their capacity when batteries handle the local difference between supply and demand.^[39]

Storage plants can also be used in combination with an intermittent renewable energy source instand-alone power systems.^[40]

While the energy storage capacity of grid batteries is still small compared to the other major form of grid storage,pumped-storage hydroelectricity with 200 GW power and 9000 GWh energy storage worldwide as of 2025 according toInternational Hydropower Association,^[100] the battery market is catching up very fast in terms of power generation capacity as price drops.^[101] Average world system price was around $120/kWh in 2025.^[5]

Relative to 2010, batteries and photovoltaics have followed roughly the same downward price curve due toexperience curve effects.^[102] Cells are the major cost component, costing 30-40% of a full system.^[99]

By mid-2025, China passed 100 GW batteries (164 GW total storage).^[103] At the end of 2024, China had 62 GW / 141 GWh of battery power stations.^[104] In 2020, China added 1,557 MW to its battery storage capacity, while storage facilities forphotovoltaics projects accounting for 27% of the capacity,^[105] to the total 3,269 MW of electrochemical energy storage capacity.^[106] As of May 2025, China’s cumulative BESS installations are reported at 106.9 GW and 240.3 GWh, with global battery storage deployment of nearly 9 GWh in April 2025.^[107]

The United States installed 12.3 GW / 37.1 GWh of batteries in 2024.^[108] In 2022, US capacity doubled to 9 GW / 25 GWh.^[109] At the end of 2021, the capacity grew to 4,588 MW.^[110] The 2021 price of a 60 MW / 240 MWh (4-hour) battery installation in the United States was US$379/usable kWh, or US$292/nameplate kWh, a 13% drop from 2020.^[111][112] In 2010, the United States had 59 MW of battery storage capacity from 7 battery power plants. This increased to 49 plants comprising 351 MW of capacity in 2015. In 2018, the capacity was 869 MW from 125 plants, capable of storing a maximum of 1,236 MWh of generated electricity. By the end of 2020, the battery storage capacity reached 1,756 MW.^[113][114] The US market for storage power plants in 2015 increased by 243% compared to 2014.^[115]

In June 2024 the capacity was 4.6 GW of power and 5.9 GWh of energy in the United Kingdom.^[116] In 2022, UK capacity grew by 800 MWh, ending at 2.4 GW / 2.6 GWh.^[117] As of May 2021, 1.3 GW of battery storage was operating, with 16 GW of projects in the pipeline potentially deployable over the next few years.^[118]

As of the end of 2024, Europe had reached 61 GWh of installed battery energy storage capacity, after adding 21 GWh that year. Germany and Italy each contributed approximately 6 GWh to this growth.^[119] The average installation cost during 2024 ranged between €300 and €400 per kilowatt-hour.^[99] By comparison, Europe deployed 1.9 GW of new battery capacity in 2022.^[120] Developments in Germany are closely monitored byRWTH Aachen University sitebattery-charts.de, reporting^[121] in September 2025 15 GW and 22 GWh mostly in over 2 million home-based systems, while 1.84 Mio. registered Battery Electric Vehicles (BEVs) in Germany have an estimated energy capacity of over 115 GWh.

Japan’s energy sector has also undergone significant growth in renewable energy capacity. expanding by over 30% within five years, which has contributed to a sharp increase in demand for battery energy storage systems (BESS). More than half of the 2.4 GW of BESS capacity awarded in recent long-term low-carbon power auctions was allocated to foreign-owned companies or consortia. Projects approved in 2024 alone comprise more than 1.37 GW of power capacity and over 6.7 GWh of energy capacity.^[122] The country’s Long-Term Decarbonization Power Source Auction supports BESS deployment by guaranteeing fixed cost recovery over a 20-year period. However, constraints such as limited price volatility and a price floor in Japan’s power market may limit investment returns for storage operators, signaling the need for further regulatory reform.^[123][124]

Worldwide in 2024,CRRC had 8% market share,Sungrow 14%, andTesla Energy 15%.^[125]

Some developers are also utilizing retired electric vehicle batteries to build second-life storage systems, with costs potentially 50% lower than those of new battery installations.^[126] Nonetheless, due to the declining cost of new batteries, buyers of second-life systems may only be willing to pay around 10% of the original cost.^[102] In 2024, a 53 MWh battery storage facility built from approximately 900 used electric vehicle batteries was commissioned in Texas.^[127]

Loom Solar has announced the launch of its scalable 125 kW/261 kWh CAML battery energy storage system (BESS), which can be scaled up to 1 MWh, designed to replace diesel generators in the commercial and industrial (C&I) segment.^[128]

Following the major2025 Iberian Peninsula blackout, which severed the Iberian grid from the rest of Europe on 28 April in just five seconds and caused some deaths plus economic losses estimated at up to €4.5 billion, the importance of system resilience has become increasingly prominent in Spain. Battery Energy Storage Systems were at a very low level at less than 20 MW, but are now regarded as a key pillar of the Spanish energy transition.^[129] Major utilities such as Iberdrola and Solaria are now actively developing hybrid solar-plus-storage projects to mitigate the impact of solar overproduction and declining market prices. Solaria alone has launched eight new BESS installations in Castilla y León and Castilla-La Mancha.^[130]

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