State-of-the-art batteries boost European energy transition

Yesterday, major battery news broke: the Dutch company Ore Energy raised 38 million euros to further scale up its iron-air battery. The Delft-based startup is working on what’s known as a “rust battery.” This news is part of a broader trend. Across Europe, a new generation of battery technologies is emerging that aims to reduce dependence on lithium-ion batteries.

Iron-air batteries: rust as the key to long-term storage

Ore Energy, based in Delft, is the first in the world to connect an iron-air battery to the power grid. This “rust battery” stores energy through a reversible chemical process: iron reacts with oxygen from the air, producing rust. During charging, the rust is converted back into pure iron, releasing the stored energy🔗︎. The system, tested at The Green Village on the TU Delft campus, can store power for up to 100 hours—a crucial advance over lithium-ion batteries, which typically last only 4 to 12 hours🔗︎.

With a new investment of €38 million, Ore Energy is now building its first factory, focused on modular systems suitable for large-scale applications🔗︎. The technology uses exceptionally inexpensive and abundant materials: iron, water, and air. As a result, the battery is not only 50% cheaper than lithium-ion, but also safe and fully recyclable🔗︎.

Flow batteries: liquids as a storage medium for solar and wind

Elestor B.V. has developed another promising technology: flow batteries. These systems store energy in liquids, with hydrogen and iron (or, more commonly, bromine) serving as active materials🔗︎. A major advantage is the separation between power (MW) and capacity (MWh), which makes the batteries easily scalable for applications ranging from the megawatt-hour to the gigawatt-hour level. Elestor’s hydrogen-iron flow battery is specifically designed for long-term storage and can compete with lithium-ion batteries in applications lasting longer than eight hours🔗︎. The company, which collaborates with organizations such as Fraunhofer ICT and Eindhoven University of Technology, already has a 3 MWh pilot project for Vopak and plans to expand to 250 MWh🔗︎. The technology is not only cost-effective but also environmentally friendly: by 2026, Elestor will have already avoided 355,786 metric tons of CO₂ emissions🔗︎.

Sodium-ion batteries: an affordable and safe alternative

Europe is also investing in sodium-ion batteries, which use sodium (from sea salt) instead of lithium. This technology offers advantages such as lower costs, better availability of raw materials, and inherent fire safety🔗︎. Although the energy density (100–175 Wh/kg) is lower than that of lithium-ion (120–270 Wh/kg), sodium-ion batteries are ideal for stationary storage and smaller electric vehicles🔗︎. CATL, the world’s largest manufacturer, is already supplying 5 GWh of sodium-ion batteries to Europe, in collaboration with the Dutch company Alfen🔗︎. The technology performs well at low temperatures and could eventually compete with lithium iron phosphate (LFP) batteries, with expected costs of €40–50 per kWh starting in 2027🔗︎. Dutch and European players, such as UNIGRID Battery, are working on local production to reduce dependence on Asian suppliers🔗︎.

Impact on Europe: autonomy, affordability, and sustainability

These innovations strengthen Europe’s autonomy in the field of energy storage. Ore Energy’s iron-air batteries and Elestor’s flow batteries use locally available materials, reducing dependence on critical raw materials such as lithium, cobalt, and nickel🔗︎. This aligns with the EU’s strategy to accelerate the energy transition and make the supply chain more resilient🔗︎. Sodium-ion batteries contribute to these goals by offering a cheaper and more environmentally friendly alternative for large-scale storage🔗︎.

In addition, Dutch and European subsidies, such as the Circular Batteries Subsidy Scheme (SCB) and the Manufacturing Industry Climate-Neutral Economy Investment Subsidy (IMKE), stimulate the development and production of these technologies🔗︎. This step not only lowers costs for consumers and businesses but also stabilizes the power grids by better accommodating peaks and troughs in renewable energy generation🔗︎.

Future outlook: scaling up and commercial breakthrough

The coming years will be focused on scaling up. Ore Energy plans to build a factory with a capacity of 1 GWh in 2028, followed by a larger facility in 2029🔗︎. The company aims for 50 GWh of annual production by 2030, based entirely on European materials🔗︎. Elestor is expanding its operations to the U.S. and other markets, with a focus on large-scale storage for solar and wind farms🔗︎. For sodium-ion batteries, the International Energy Agency (IEA) expects 2026 to be a pivotal year, with mass production set to begin in 2027🔗︎. The first sodium-ion-based home batteries are expected in Europe between 2027 and 2028🔗︎.