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Flow batteries are emerging storage technologies for data centers to military microgrids

Energy storage is becoming increasingly important to the power industry. Lithium-ion battery technology has been implemented in many locations, but flow batteries offer significant benefits in long-duration usage applications and situations that require regular cycling throughout the day.


With the increasing demand for continuous power supply in all major countries, the need
for energy backup has increased. Flow batteries perform the function of acting as a backup
source of power in case of power cuts or peak loads. The flow batteries are looked upon as
a substitute for fuel cells and lithium-ion batteries. The rechargeable property and scalability of the flow batteries just by using the required amount of electrolyte acts as a unique factor bifurcating it from other available substitutes.


The used electrolyte can be again stored in storage tanks making the operation of flow
batteries more flexible. The long operational life and low maintenance are the other
advantages offered by the flow batteries. With the increasing adoption of renewable
sources of energy, namely solar and wind, the demand for batteries has increase, which in
turn has affected the growth of the flow batteries market. This trend is set to continue all
around the globe with green energy targets set up by various developed and developing


In a redox flow battery, catholyte and anolyte are stored in separate tanks, and pumps are used to circulate the fluids into a stack with electrodes separated by a thin membrane. This membrane permits ion exchange between the anolyte and catholyte to produce electricity. The power produced is dependent on the surface area of the electrodes, while the storage duration is a function of the electrolyte volume. For some technologies, the power and energy can be scaled independently, allowing for an easily customizable battery.


With life spans reaching up to 30 years, depending on the electrolyte chemistry, flow batteries may provide unrivaled cost certainty versus other emerging storage technologies on the market. Though flow batteries currently represent a higher upfront capital investment than a similar-sized lithium-ion configuration, they become more competitive when evaluated on a total cost of ownership over a 20- to 30-year lifecycle. Moreover, costs are dropping for flow batteries as technology advances and manufacturing efficiencies are implemented.


In the utility space, flow batteries are best suited for longer discharge durations (six hours or more) in megawatt-scale power increments. Certain use cases favor flow batteries over other storage types.


Various types of flow cells (batteries) have been developed, including inorganic flow battery and organic flow batteries.   Under each category, flow battery design can be further classified into full flow batteries, semi-flow batteries, and membraneless flow batteries. Though there are dozens of different types of flow batteries, only about 10 to 12 specific chemistries appear ready for commercial applications. All operate on the same basic principle of incorporating liquid electrolyte to function as a source of direct current (DC) electricity that runs through an inverter for conversion to alternating current (AC) power.


Vanadium redox flow batteries are the most marketed flow batteries at present, due to the advantages they provide over other chemistries, despite limited energy and power densities. Since they use vanadium at both electrodes, they do not suffer cross-contamination. The limited solubility of vanadium salts, however, offsets this advantage in practice.


Redox flow battery equipped with vanadium material is the electrochemical energy storage system suitable for a broad range of renewable energy applications and is witnessing developments to reduce the carbon footprint of electricity generation. Flow batteries equipped with vanadium material are mostly adopted and commercialized for utilities, commercial, and military applications.


Flow batteries can be configured as both a single tank, usually for smaller applications, or as a dual tank, usually on a larger footprint. The single-tank systems typically feature zinc or other metal batteries, while dual-tank systems require electrolyte comprised of saltwater, iron, vanadium, or other minerals.


For applications where multiple charge/discharge cycles are required each day, flow batteries are available within milliseconds as loads dictate and they can quickly recharge from a variety of available power sources. In fact, depending on tank configurations, flow batteries can discharge and recharge simultaneously, providing power capacity or voltage support almost indefinitely. Attributes of flow batteries include:

    ■ Demonstrated 10,000-plus battery cycles with little or no loss of storage capacity.
    ■ Ramp rates ranging from milliseconds for discharge if pumps are running, to a few seconds if pumps are not.
    ■ Recharge rates for flow batteries also are reasonably fast.
    ■ Wide temperature ranges for operation and standby modes compared to lithium-ion options.
    ■ Little or no fire hazard.
    ■ Chemistries that pose limited human health risk due to exposures.
    ■ Easy scale-up of capacity by adding electrolyte volume (although that may involve more tanks and piping).

The world’s biggest flow battery opens in China

The world’s largest flow battery has opened, using a newer technology to store power. The Dalian Flow Battery Energy Storage Peak-shaving Power Station, in Dalian in northeast China, has just been connected to the grid, and has been operating since October 2022.


The vanadium flow battery currently has a capacity of 100 MW/400 MWh, which will eventually be expanded to 200 MW/800 MWh. According to the Chinese Academy of Sciences, who helped develop the project, it can supply enough electricity to meet the daily demands of 200,000 residents. It will be used to smooth peaks and troughs in Dalian’s electricity demand and supply, making it easier to use solar and wind power.


Flow batteries are a newer type of battery technology that operate by combining tanks of liquid electrolytes, rather than using static electrodes. They use cheaper and more sustainable materials than lithium-ion batteries, and are longer-lasting: theoretically, vanadium flow batteries could charge and discharge indefinitely. They’re also flame-resistant and therefore safer than lithium-ion.


Integration of artificial intelligence in flow batteries

In order to accelerate the commercialization of flow batteries, the accurate prediction of cost and
performance of the vanadium flow battery stack has become a necessity. A research team from the
Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences has suggested a
machine learning-based strategy, artificial intelligence (AI). The use of AI helps in the prediction of performance and cost and optimization of vanadium flow batteries. The technology helps
enhance efficiency, provides guidance for the R&D activities of vanadium flow batteries, and reduces the research time. It also predicts the energy efficiency, voltage efficiency, power & energy cost of the vanadium flow battery system with high accuracy and the utilization rate of electrolyte of the vanadium flow battery stack.


DOD requirement

Fort Carson, a US military base, has contracted Lockheed Martin to build a 10 MWh redox flow battery to store its solar farm’s energy. Why has this military base opted for this technology? Well, it has a nearly-infinite life cycle, almost no degradation, huge safety margins, is nearly 100% recyclable, is incredibly eco-friendly, and all while being astonishingly cheap.


Defense Department Continues Research into Vanadium Flow Batteries with Ameresco, reported in April 2021

The US Department of Defense has begun its second phase of research into vanadium flow batteries in partnership with Ameresco, a developer of clean energy and microgrid projects. Phase two of the research is designed to examine the potential of vanadium flow batteries in military microgrids. The experiment will test the validity of the battery’s potential to decrease reliance on diesel fuels and lower the cost of critical load support through hardware in the loop systems.


The test is one of several underway into the potential of vanadium flow batteries for microgrids as a replacement for gas generators or lithium-ion storage. Vanadium flow batteries have also helped support electrical outages during California wildfires, and they are currently planned for use in Africa’s first megawatt scale flow battery microgrid.


Flow Batteries market

The global flow battery market size is estimated to be USD 214.3million in 2021 and projected to reach USD 489.6million by 2026, at a CAGR of 18.0%. The increase in telecommunication tower installation and rising adoption of flow batteries in utility application is driving the growth of the flow battery market. Moreover rising requirement for power supply which results in increase in the number of data centers as well as growing technological innovation with improved capabilities in the flow batteries is also expected to drive the growth of the market in the near future.


DRIVERS: High demand for flow batteries in utilities

Utilities are among the early application areas of flow batteries, as they deal with the penetration of renewable energy across the grid. In utilities, flow batteries are ideal for extensive discharge
duration in MW scale power increment. Besides, they avoid interrupted power supply and transfer energy during the disruption of grid services. To date, most of the flow battery installation projects worldwide cater to the requirements of utilities. In recent years, due to the growing need for electrification in rural and urban areas, government and private bodies are improving the electric grid system to cater to energy need. The governments of various countries are also making high investments in grid development, owing to the rising demand for electricity.


RESTRAINT: Requirement of high initial investment for manufacturing of flow batteries
Over the years, flow battery has evolved as a potential substitute for conventional batteries,
including lithium-ion battery, lead-acid battery, and sodium-based battery; however, the high cost of flow batteries can act as a major restraining factor for the market growth. The overall cost associated with the flow battery includes component, material, installation, and repair & maintenance costs, which are extensive investments for small- and medium-sized enterprises. Besides, the components and chemicals used in most of the flow batteries are rela


The manufacturers of flow batteries face fierce competition from the providers of widely adopted
conventional batteries, such as lithium-ion, lead-acid, and sodium-based. Among these, lithium-ion batteries are the most popular and widely used. They are highly used in the transportation sector, consumer electronics industry, and stationary applications. A flow battery is a relatively new battery technology. Some of its types are still in the early phase of commercialization compared to the other battery technologies, such as lead-acid and lithium-ion.


Market Segments

The global flow battery market is broadly classified into two types, namely hybrid and redox. The redox flow batteries are the most used batteries due to the shorter payback period and better capacity retention even after many cycles. On the basis of its application, the global flow battery market can be segmented into power, automotive, residential, industrial, energy storage, and others. The increasing demand for electricity and increased adoption of solar and wind power has seen the power segment hold a larger market share in the global flow battery market. The adoption in the power segment will continue to grow owing to the need for continuous power and coming up with new utility grids.


Large-scale flow battery is expected to have largest CAGR during the forecast period
A large-scale flow battery is the most common type of flow battery used today. Flow batteries have
always been bulky and require more space as their design includes two large external tanks where
the electrolytes are stored. These batteries are based on reversible chemical reactions. Besides, the
charging and discharging of large-scale flow batteries do not degrade the electrolytes or the cell,
resulting in extended battery life compared to other batteries. Large-scale flow batteries are durable



The global flow battery market is segmented into North America, Europe, Asia Pacific, Latin
America, and the Middle East and Africa. The USA holds the largest market share in the
North America region and globally owing to the rising demand for continuous electricity
supply. As most of the countries in Europe have increased power generation using
renewable sources of energy, the need for the battery for energy storage has also
increased. Germany, Italy, France, UK are the major players in the region.


The increasing energy demand and urbanization have seen the Asia Pacific region hold a significant opportunity for the growth of the global flow battery market in the region. In Asia Pacific major countries adopting batteries storage systems have looked up to flow batteries
potential replacements for lithium-ion batteries due to less maintenance, faster payback period and scalable capacity. Also, the growing automotive sector in the region has impacted the growth of flow battery sales in the region.


The Asia Pacific is expected to be the fastest-growing region during the forecast period.
Growing adoption of energy storage solutions in industrial and utilities, as well as an increasing number of operational projects with flow battery installations are expected to fuel the growth of the regional market during the forecast period. Countries such as China, Japan, India, and Australia are striving to boost their large-scale energy storage capacity through battery technologies which could, in turn, enhance electric stability. In addition, the increase in renewable energy investments, regulations demanding energy efficiency, expansion of power generation capacities, electrification of the transport sector, and decline in the costs due to technological advancements in developing countries in APAC are supporting the growth of the flow battery market.


Latin America and the Middle East region will see moderate growth in the flow battery market with the increasing adoption of renewable sources in the region. Africa, Brazil, Chile are the dominant players in the regions.



The key players in the global flow battery market are Enervault, Imergy Power Systems,
Primus Power, Prudent Energy, EnSync Energy Systems, Redflow – sustainable Energy
Storage, Sumitomo Electric, Aquion Energy, Redflow Limited, Smart Energy, EnSync Energy
Systems, UniEnergy Technologies, VIONX Energy Corporation, and VoltStorage GmbH.



In May 2019, The California Independent System Operator(ISO) has become the first US wholesale power markets to connect a groundbreaking type of flow technology battery to its grid. This adoption of flow batteries could lead to the development of storage capabilities on a large scale. The new storage technology would be evaluated for over 4 years.

In May 2019, As per the Journal of American Chemical Society, the researches combining from various societies have found the solution to the decomposing of organic anthraquinone molecules which powered their groundbreaking battery. The solution included not only the decomposition of the molecules but also how to mitigate and reverse the decomposition and bring molecules back to life.

In April 2019, Chemours Company which is an American chemistry firm has combined with UniEnergy Technology which is a redox flow battery manufacturer headquartered in Washington with the target of increasing flow battery technology uptake in the market




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