Ali Tuna from Modern Battery (MoBat) Group of the University of Turku in Finland introduces a new neutral-pH flow battery that tackles Europe’s energy storage and materials dependency challenges – offering a safer, scalable alternative to vanadium systems.
Europe is undergoing the fastest energy transition in its history. Solar and wind farms are expanding across the continent, but there’s one big challenge holding them back – storage. Without reliable energy storage, renewable power risks being wasted during periods of over-production and insufficient use during peak demand. However, while lithium-ion batteries have dominated headlines, they are far from the ideal solution for large-scale, long-duration storage.
Flow batteries have emerged as a promising alternative, but the sector is still constrained by high costs, material dependencies and other issues. In order to become ‘material independent’, Europe must embrace new innovations.
This is where the University of Turku’s work comes in – a new chemistry adopted for flow battery technology, designed to redefine the role of flow batteries in achieving energy security and material independency.
(Electro)chemistry matters
Flow batteries are fundamentally different from conventional battery systems (Li-ion, PbA, Ni-MH, etc). Instead of storing energy in solid electrodes, they use two electrolyte solutions separated by an ion exchange membrane (Fig 1).
Their key strength lies in their scalability, where the energy capacity depends on the size of the electrolyte tanks and the power depends on the cell stacks. This makes them ideal for stationary grid applications where long-duration storage is needed. But, chemistry matters! So, let’s have a look at what’s available on the market.
Today’s commercial flow batteries are largely based on vanadium chemistry. Vanadium flow batteries (VFBs) are robust, proven and already deployed at megawatt scale in several countries. However, their promise is dampened by four persistent issues: cost, sustainability, material dependency and environmental impacts. Vanadium prices are volatile, supply chains are geographically concentrated, and the overall system cost remains too high for widespread deployment in Europe.
Other chemistries such as iron-chromium, zinc-bromine, organic molecules, hybrid systems and many others are being developed, but each faces challenges, including stability, toxicity, scalability, environmental impacts and efficiencies. Despite decades of progress, the flow battery industry has not yet overcome the material and cost barriers needed for true mass adoption, except for those who hold the materials.
The main challenge – material dependency
Europe has learned painful lessons about dependency. The natural gas crisis following Russia’s invasion of Ukraine exposed how vulnerable economies can be when reliant on single-source suppliers. The same risk applies to critical raw materials for batteries and renewable technologies.
Vanadium is primarily mined and refined in China, Russia, South Africa, USA and others. Lithium and cobalt, essential for Li-ion batteries, are similarly concentrated. If a supplier nation decides to restrict exports, whether for political leverage, environmental reasons or internal demand, Europe could face severe shortages. Imagine investing billions in a technology platform, only to find the raw materials no longer available. That scenario is not hypothetical; it is a real possibility.
This is the material dependency challenge, which is shifting from fossil fuels to clean energy technologies without addressing the geopolitical risks embedded in material supply chains. Energy independence cannot be achieved without material independence. Europe must look beyond today’s chemistries and develop new, sustainable alternatives.
Energy stability and blackout lessons
On April 28 2025, the Iberian Peninsula experienced one of the largest blackouts in Europe’s recent history. A sudden loss of around 15GW of generation – which is nearly 60% of national demand – plunged Spain and Portugal into darkness within seconds. The power was out for roughly half a day, disrupting the lives of tens of millions of people across both countries. There were unbelievable interruptions throughout telecommunication, transportation, healthcare, industry and more.
The human and economic toll was significant. There were casualties and injuries in both countries, mainly due to failures of medical equipment and generators. The economic losses were estimated at more than €1.5 billion (US$1.7bn), roughly 0.1% of Spain’s GDP. Can you imagine what could be done with €1.5 billion?
Integration with renewables
Renewables are abundant in Europe, but poorly matched to demand. Solar farms generate during the day, but not at night. Wind production is not predictable, leading to regional imbalances and intermittent energy production. This gap between renewable production and actual consumption can only be bridged by large-scale, long- duration storage.
A flow battery can store surplus wind and solar energy and release it when needed, creating a flexible buffer that matches renewable generation to demand curves. Without such storage, Europe’s renewable transition will always remain incomplete. The wasted energy from lack of storage is an economic loss and a climate failure. At the same time, Europe imports electricity from neighbouring regions to cover shortages, reinforcing dependence on external suppliers (Fig 2).
New technology as a Nordic innovation
Recognising these challenges, a team of four researchers at the University of Turku has developed a novel aqueous flow battery technology operating at neutral pH, similar to that of salty water, without requiring corrosive acid and alkaline solutions. Unlike strong acidic and alkaline systems, this chemistry is environmentally benign, safer to handle, and avoids reliance on critical raw materials. The electrolyte materials are more cost-effective and abundant, opening the door to sustainable scaling.
This system retains the core advantages of flow batteries such as scalability, long-duration storage, and decoupling of power and energy, but eliminates many of the drawbacks associated with vanadium. It represents not just an incremental improvement but a fundamentally different approach.
The research team is progressing from technology readiness level (TRL) 4 toward TRL 5 following preliminary support from the City of Turku and Boost Turku, which recognising and completing both the proof-of-principle (PoP) and initial proof-of-concept (PoC) demonstrations of the new flow battery technology. Building on these results, the team now aims to reach TRL 7 by 2027–2028 through extended piloting, prototyping, and post-PoC development under a larger grant framework.
After laboratory tests and analysis, the patent application was filed in March 2025, with international filing under the Patent Cooperation Treaty anticipated in 2026. Current and future projects will allow the team to transition from laboratory demonstrations to pilot-scale prototypes, bridging the gap toward commercialisation. The researchers are intensively working on this direction (Fig 3).
The advantages of the system include:
- Sustainability: Neutral pH, non-toxic, reduced environmental impact
- Cost-effectiveness: Avoiding expensive and volatile raw materials
- Feasibility: The materials can be easily sourced in Europe. Preliminary feasibility studies have been carried out to detect production limits alongside continental Europe and neighbouring countries
- Scalability: For community-level to grid-scale applications
- Safety: Improved handling and reduced risks compared to highly corrosive, acidic and alkaline systems
- Chemistry: Good oxygen resistivity, high water solubility, easy to prepare, excellent stability, very good compatibility.
The team is developing different electrochemically active materials – as an example, the flow battery setup provides 1.25V two electron system with double the capacity compared to VFBs. The battery potential can be extended to >1.35V using various negolyte materials to combine with the team’s patent-pending posolyte materials.
From Finland to Europe
Finland has a long tradition of innovation, having invented and hosted technologies that have left a global mark, from communication systems and mobile devices to clean energy solutions and digital platforms. This culture of combining scientific excellence with practical application has positioned Finland as a trusted hub for technological breakthroughs, where new ideas are developed and transformed into successful businesses and scalable global solutions.
The research team is made up of four inventors; Ali Tuna (PI), Vahid Abbasi, Chanez Maouche and Pekka Peljo. Although the project began at the University of Turku, its relevance extends across the Nordics, Baltics, Europe to the globe as a whole. Energy security is not a local issue, it is regional and global. The Nordic grid is highly interconnected, and disruptions in one country can ripple across borders. But the time has come to act as one, supporting each other, making a great future together.
Europe has set ambitious targets for carbon neutrality by 2050, with interim goals for 2030. Meeting these targets requires not only renewable expansion but also reliable storage. Without it, fossil backup plants will remain in operation, undermining climate goals. By investing in innovative flow battery technologies, Europe can reduce dependency on external suppliers, strengthen grid stability, and lead in a global market projected to grow exponentially in the coming decades.
Invitation to build an independent energy future
The race for critical materials is intensifying worldwide. Nations are competing for lithium, cobalt, nickel, and vanadium, often at the expense of environmental standards or geopolitical stability. In this environment, Europe must chart a different path.
The recent Iberian blackout showed us the cost of instability. The energy crisis of recent years showed us the cost of dependencies. Now, Europe faces a choice: either continue down the path of reliance on scarce materials, or invest in new technologies that secure our independence.
We must also consider all of the risks and impacts of these materials used in batteries, as we are responsible for both the environment and the next generations. The flow battery has come forward to be a good candidate as reliable and sustainable storage solution.
The University of Turku’s aqueous flow battery innovation is a step toward the latter. By combining sustainability, cost-effectiveness, environmental-friendliness and scalability, this approach addresses not only the technical demands of energy storage but also the political and economic realities of material supply.
Energy security is about more than keeping the lights on. It is about sovereignty, stability and resilience. Europe must decide whether it will remain dependent, or stand resilient with innovations that reflect its values and ambitions.
