BEST magazine reports from the opening session of the International Flow Battery Forum in Budapest and finds an industry gathering commercial momentum in Asia, Europe and North America. Projects and factories are becoming larger, but finance, regulation and a dependable supply chain will determine how quickly flow batteries secure their place in long-duration energy storage.

The first session of the International Flow Battery Forum (IFBF) in Budapest on 16 June carried a title that sounded like a declaration: “2026, it’s time for flow batteries.” For an industry accustomed to explaining what its technology can do and why it deserves a place alongside lithium-ion, it signalled a new found confidence and self-determination.

The panel brought together Kees van de Kerk, president of Flow Batteries Europe; Jeehyang Huh of South Korean manufacturer H2; Jonathan Marren, CEO of Invinity Energy Systems; Min Tang of China’s Rongke Power; Christoph Stelzer of CellCube Energy Storage; and Eugene Beh of US organic flow battery developer Quino Energy. Their contributions converged on the conditions needed to turn successful projects into a repeatable industry.

Budapest provided an Eastern European setting for a discussion that ranged from Korean industrial installations and Chinese utility projects to UK policy and a vast Swiss battery planned alongside an AI data centre. Flow battery deployments were once scattered demonstrations. The examples discussed at IFBF included operating commercial systems, gigawatt-hour-scale manufacturing and projects large enough to form part of energy infrastructure.

The opening session was optimistic without being triumphalist: the technology has advanced while the commercial system around it is still being assembled. Capital costs remain high, manufacturing capacity is small beside the lithium-ion industry and investors want longer operating records. Policy for long-duration energy storage (LDES) remains inconsistent.

Anthony Price – building with style

Everything that we do leaves a footprint. For many of us, we have recently been concerned with the carbon footprint of our work, but there are many other things that we should consider. Electrical infrastructure may not be the most elegant things on the planet, but it does not have to be like that.

Early power stations were often built to a high standard – think how we grew to love Battersea Power Station in the centre of London. We even put batteries in some very attractive buildings, and some of these buildings are still in use today.

I have visited a number of battery projects, from the days when lead-acid was prevalent, to the present. I have seen good, and not so good structures. But what do we have nowadays, I regret that for most, battery storage is just a collection of ISO shipping containers. Many present day developers must be embarrassed – because so many of them choose to surround their batteries with trees. But these fields of shipping boxes take up valuable land, destroying the amenity, and leaving a legacy of annual painting that makes the Forth Rail Bridge seem like a kindergarten project. We should raise the bar.

I want to challenge the flow battery community to not only present the best commercial case for choosing flow batteries over other types, and not only rest on improved technical performance and environmental benefits, but to leap over the bar with some top class design. Good building design enhances local neighbourhoods, creates social pride, lifts the spirit of all those that see it, and raises the profile of the building and its function. Good building design is a cornerstone of good operational use of the battery assets inside. We need to encourage good design.

So, there will be a Swanbarton® IFBF ® architecture award; covering two categories:

1. Stand-alone flow battery building
2. Flow battery incorporated into an existing building

Contact Swanbarton for more information: info@swanbarton.com

The images in this article were part of a presentation by Anthony Price and show the locations of various battery installations. He spoke about a forthcoming architecture award (see the boxout on the right) a drive towards improving the elegance of batteries in the field, or elsewhere

Duration finds a market

The case for flow batteries begins with changes to the electricity system. Wind and solar generation are expanding, electrification is adding new demand and grid connections are becoming a constraint in many markets. Curtailment is increasing where renewable output exceeds the network’s capacity to use or move it at the time of generation. At other times, renewable generation leaves a gap that must be met by dispatchable power.

Short-duration batteries have already become a familiar part of the response. Lithium-ion systems are effective at fast-response frequency services, peak shifting and other applications in one- to four-hour scenarios. Higher renewable penetration creates demand for storage that can discharge for longer, cycle intensively, and remain in service for decades.

Flow batteries store their electrolyte in external tanks and pump it through electrochemical stacks. Tank volume determines energy capacity, while the stacks determine power, allowing duration to be extended without reproducing every part of the system.

The familiar advantages were repeated in Budapest: many systems use aqueous, non-flammable electrolytes and offer deep discharge, high cycle life, limited degradation and operation over 20 years or more. Energy density carries less weight beside a renewable plant, industrial site or substation.

Kees van de Kerk, president of Flow Batteries Europe, noted: “The goal is not to beat lithium at being lithium. The goal is to be indispensable where lithium is the wrong answer.” Flow batteries do not need to reproduce lithium-ion’s combination of compactness, an enormous manufacturing base and low initial cost.

This more precise positioning ran through the session. The storage market is dividing by use rather than settling on one chemistry. Lithium-ion retains compelling advantages for mobile applications, short-duration storage and installations with tight space constraints.

Projects get larger

China supplies the clearest evidence of growing scale. Rongke Power says it has deployed more than 3.5GWh of vanadium flow batteries worldwide, and Chinese projects have moved the technology firmly into utility territory. Min Tang presented that record as proof of commercial readiness as well as electrochemical performance. Large installations require factories, project delivery teams and suppliers capable of producing consistent equipment in volume.

H2 offered a different view of the same progression. Huh discussed operation of a 1MWh commercial and industrial system and implementation of a 20MWh project in South Korea. Industrial users can combine peak shaving, energy arbitrage, demand management and backup power, while the non-flammable electrolyte addresses concerns that have become more acute following fires involving lithium-ion storage.

The company’s manufacturing plans show how quickly suppliers expect the market to develop. H2’s existing K1 factory has annual capacity of 330MWh. Its K2 plant is intended to raise annual production to 1.2GWh, producing systems for four-hour and longer-duration applications. A factory of that size remains modest by lithium-ion standards, but it represents a substantial commitment for the flow battery sector and must be supported by a credible order pipeline.

Marren outlined one of the most striking European examples: Invinity has been selected by FlexBase to design a vanadium flow battery for the Technology Centre Laufenburg on the Swiss-German border. The initial system could store up to 1.5GWh, with a possible later expansion to 2.1GWh, and will be integrated with an AI data-centre and technology campus. It is intended to support renewable energy at the site and provide grid stabilisation.

The Laufenburg project connects two themes that surfaced repeatedly in Budapest: infrastructure-scale flow batteries and the rapid growth of electricity demand from AI. Data centres require dependable power, but their computing loads can change sharply and grid connections are often constrained.

A flow battery can sit between the grid connection and the data centre load – charging when capacity is available and discharging during demand peaks. It can also bolster on-site wind or solar generation and provide multi-hour backup. Frequent cycling plays to the technology’s strengths, while the absence of thermal runaway is valuable beside critical digital infrastructure. The Swiss scheme will be an important test of that proposition on a scale far beyond the conventional demonstration project.

Utilities need storage for renewable firming, congestion relief, capacity and grid services. Industrial sites can use it for peak shaving and resilience. Hospitals, telecommunications facilities and emergency services need power during prolonged disruption. All can benefit from a battery that tolerates regular deep discharge without sacrificing much of its useful capacity.

The discipline of production

The move into larger projects transfers pressure from the laboratory to the factory. A utility-scale installation may contain hundreds of stacks, all of which must deliver closely matched electrochemical performance. Small variations in materials, assembly or process control can become costly once they are repeated across a large system.

Automation improves repeatability, permits tighter quality control and produces data needed to understand failures. Modular architectures also reduce engineering work between projects. The same equipment can be configured for a 1MWh industrial installation or repeated across a 20MWh development.

This industrialisation is beginning to lower costs. Manufacturers at the session described gains from automation, standardised products, higher volumes and supply-chain optimisation. One reported cutting product costs by roughly two-thirds in 18 months. Such progress narrows the gap with lithium-ion, although flow batteries continue to face a difficult comparison at the point of purchase.

An investor looking only at capital expenditure will often favour a lithium-ion system supported by established suppliers and a highly competitive global manufacturing chain. The flow battery industry prefers the levelised-cost-of-storage (LCOS) metric, which spreads the cost over the energy delivered during the asset’s working life. Long-life, intensive cycling and low degradation can make the result favourable even when the equipment costs more initially.

LCOS does not remove the need to finance the higher opening cost. Nor does a spreadsheet compensate for limited operational evidence. Banks, infrastructure funds and insurers want performance histories, dependable warranties, financially durable suppliers and contracts that allocate risk clearly. They also need confidence that the project will earn money throughout its life.

This makes bankability a collective exercise. A technically capable manufacturer still requires an experienced engineering, procurement and construction contractor, reliable suppliers and an owner able to operate the plant. Lenders need to understand the chemistry, while insurers need enough loss data to price the risk. Each completed project strengthens that evidence base; delays, failures, or the collapse of a supplier can affect confidence across a relatively young sector.

Rules for a long-lived asset

Revenue policy is particularly important for LDES. Electricity markets often reward fast response and short-term price arbitrage, services readily supplied by lithium-ion batteries, while failing to pay fully for duration, resilience or deferred network investment. A long-lived flow battery cannot be financed on the assumption that occasional price spikes will continue for two decades.

The UK’s cap-and-floor mechanism was cited as a useful development. It gives eligible LDES projects a minimum revenue level while limiting excessive returns, making cash flow more predictable for investors. Ten days after the forum, Ofgem named 16 projects totalling 7,645MW that it was inclined to support in the first window. The portfolio included Frontier Legacy, a proposed 65MW, eight-hour vanadium flow/zinc battery in north Wales. Final awards are expected in autumn 2026.

Storage also needs to be recognised consistently as an asset that both imports and exports electricity. In some jurisdictions, charging structures still treat it as an end-consumer when it charges and as a generator when it discharges, loading network fees or levies onto the same electricity twice. Dedicated rules for storage, sensible grid charges, and transparent connection procedures can have as much influence on project economics as an incremental improvement to a stack.

Europe’s fragmented regulatory landscape remains an obstacle. A project model that works in Britain may not transfer easily to Hungary, Germany or another neighbouring market. Definitions, tariffs, permitting, and access to ancillary-service markets vary. For manufacturers trying to standardise products, regulation can reintroduce the country-by-country complexity that industrialisation is meant to remove.

Building the chain around the battery

Scale also changes the supply-chain question. A flow battery industry requires electrolyte producers, membrane and electrode suppliers, stack factories, tank manufacturers, pumps and power electronics, as well as project developers and contractors. Vanadium brings the additional questions of commodity price, availability and the capital tied up in electrolyte.

Tang argued for producing electrolyte close to the markets where batteries will be installed. Transporting very large volumes of liquid over long distances adds expense and complexity. Regional electrolyte capacity could reduce logistics costs, create local content, and give project investors greater confidence in supply. Leasing models and the recovery of vanadium at the end of a project can also separate the enduring value of the electrolyte from the depreciating equipment around it.

Vanadium currently accounts for the largest commercial flow battery projects, but Eugene Beh’s presence on the panel reflected the development of organic alternatives. Quino Energy is working with aqueous organic electrolytes derived from abundant materials. Organic systems promise lower-cost active materials and compatibility with inexpensive equipment such as carbon-steel tanks, although they must still establish durability and bankability at commercial scale. Beh said that in four years Quino has increased the manufacturing of its electrolyte by four orders of magnitude.

The result may be a flow battery market containing several chemistries. Vanadium’s long operating record and recoverable electrolyte may suit projects whose owners place a premium on durability. Organic, iron-based, and other systems could serve applications where material cost or regional availability dominates. The market is large enough for suppliers to pursue different balances of cost, life, efficiency, and operating conditions.

H2’s factory expansion, Rongke Power’s deployment record, and Invinity’s proposed Swiss system provide tangible signs of progress. Renewable generation is increasing the need for duration, while industry and AI are making dependable power more valuable.

Flow batteries still carry higher initial costs, a narrower supplier base and less operating evidence than lithium-ion. Those disadvantages will be reduced one factory and one completed project at a time. Policy will decide whether developers can earn predictable returns while that evidence accumulates.

The sector left its first Budapest session with a defined commercial territory: long-duration, heavily cycled and safety-critical stationary storage. Its next phase will be measured in repeat orders, standard products and finance secured without exceptional public support. Chemistry remains important, but delivery at scale will decide how much of the expanding storage market flow batteries can claim.

Funding sources

Helping European manufacturers progress beyond Europe

Peteris Ustrubs spoke at the IFBF on the funding available to European battery manufacturers. He is a Latvian diplomat and director for Asia and the Pacific at the Directorate General for International Partnerships of the European Commission.

As the global energy transition accelerates, the European Union is increasingly recognising the strategic importance of long-duration energy storage. For Europe’s flow battery industry, this presents a significant opportunity. Through its €300 billion Global Gateway investment programme, the European Commission is creating funding pathways that can help manufacturers bring their technologies to rapidly expanding international markets.

While renewable generation often dominates the conversation around decarbonisation, the Commission has stressed that energy storage is equally essential if clean power is to be deployed reliably and at scale. In particular, flow batteries were identified as a technology capable of supporting the next generation of renewable energy projects, grid infrastructure and industrial energy systems.

Rather than providing direct grants to manufacturers, the Global Gateway delivers support through a blend of grants, guarantees and technical assistance via organisations including the European Investment Bank (EIB), the European Bank for Reconstruction and Development (EBRD) and national development finance institutions. These mechanisms are designed to de-risk projects, improve access to finance and encourage private investment in strategic infrastructure.

One of the programme’s most valuable tools for the flow battery sector is the Global Gateway Investment Hub. Created to increase private-sector participation, the Hub provides a single point of entry for companies seeking EU support. Manufacturers can work through their national “Team Europe” networks – typically involving government departments, export credit agencies and development banks – to submit projects and gain access to the Commission’s financing toolkit.

The market opportunities are considerable. The Commission highlighted strong demand for energy storage across Central Asia, ASEAN, the Pacific and India, where investment in renewable energy, grid interconnection, microgrids and data centres is driving demand for long-duration storage solutions. These are applications where flow batteries can offer clear technical advantages, particularly in grid-scale and multi-hour storage deployments.

For Europe’s flow battery manufacturers, the message is straightforward. The funding mechanisms are already in place, the international demand is growing, and the Commission is actively encouraging companies to bring forward projects. Businesses that engage early with the Global Gateway Investment Hub and their national Team Europe contacts will be well positioned to secure investment and establish a stronger presence in the next wave of global energy infrastructure, while accelerating commercial deployment of innovative European flow battery technologies worldwide.