Ore Energy, a Netherlands-based energy startup pioneering iron-air long-duration energy storage, today announced that it has successfully connected its flagship iron-air battery system to the electric grid in the city of Delft — the first iron-air system to be grid-connected and fully operational anywhere in the world.
The pilot system is also the first long-duration energy storage (LDES) solution to be entirely designed, built, and installed within the European Union. The first-of-its-kind deployment represents a significant technological milestone in long-duration energy storage and marks a defining moment in European energy sovereignty and resilience.
I spoke to Aytaç Yilmaz, co-founder and CEO, and Bas Kil, Business Development Manager at Ore Energy, to learn more.
The core principle of iron-air long-duration energy storage is based on rusting and derusting iron. Yilmaz explained that “when the battery discharges, iron oxidises and forms a special type of rust.
“The system charges by using electricity to convert iron oxides (such as rust) back into metallic iron. During discharge, the metallic iron reacts with oxygen from the air to form iron oxides again, releasing electrical energy in the process.”
“The core chemistry was first developed in the 1960s for use in electric vehicles. But with limited market demand at the time, the technology was shelved.
Today, with the rise of renewables and the urgent need for affordable, long-duration energy storage, it’s finally the right moment for this kind of solution.”
Why an iron-air battery?
Where lithium-ion peaks at 4 to 8 hours of storage, Ore Energy’s iron-air battery holds power for 100 hours or more, enabling multi-day load shifting, better integration of renewables, and reduced need for fossil backup. Unlike conventional batteries, which rely on scarce or flammable materials, Ore’s iron-air chemistry uses safe, abundant elements with no reliance on lithium, cobalt, or rare earths.
Ore Energy’s iron-air battery directly addresses several systemic challenges in Europe’s energy transition:
Reduces renewable energy curtailment.
Europe is already wasting vast amounts of clean energy simply because there’s nowhere to store it when demand drops.
Ore Energy’s 100-hour battery captures surplus power across multi-day periods, cutting curtailment by up to 44 per cent in modelled systems and helping shave billions off Europe’s energy bill. -
Improves grid stability and reduces reliance on fossil fuel backup.
Even modern grids with renewables like wind or solar still lean on gas-fired power during multi-day lulls in generation. These fossil fuel “peaker plants” are costly, carbon-intensive, and erode the economics of decarbonisation. Ore Energy enables renewables to meet demand without fossil backup, something current batteries can’t do.
Saves on overbuilding and grid upgrades.
Without long-duration storage, grid operators must overbuild renewables to ensure reliability, which inflates system costs and strains grid infrastructure. Yilmaz shared that the company’s system is around seven to ten times cheaper than lithium-ion batteries, “primarily because we use iron and air — materials that are abundant, safe, and inexpensive. Among long-duration options, this is currently the most cost-effective chemistry available.”
By reducing peak capacity requirements and enabling time-shifting, Ore’s batteries cut system-wide costs by up to 63 per cent in modelled future energy systems.
Eliminates foreign supply chains for full European energy independence.
Utilities are under growing economic and regulatory pressure to reduce dependence on foreign-controlled supply chains, especially for critical materials and rare earths, which are heavily concentrated in China and conflict-prone regions.
Ore Energy’s iron-air batteries are made in-house from abundant, EU-sourced materials. They are being built with a fully European supply chain, aligned with the EU’s Critical Raw Materials Act and energy sovereignty agenda.
Ore Energy’s 100-Hour battery tackles long-duration storage challenges
According to Kil, the company is focused on three key application areas:
Co-location with renewables, particularly wind.
“Wind generation is highly variable — you can get days of high or low output in a row. Lithium-ion’s short duration doesn’t help much in that context. But our 100-hour battery is ideal for shifting large volumes of energy over multiple days.”
Grid-scale flexibility. As utilities phase out gas and coal plants, they need new ways to match supply and demand. The batteries can help stabilise the grid as it transitions to renewables.
Data centres. Data centres consume enormous amounts of electricity and are under pressure to decarbonise.
“Our batteries offer them flexibility, cost savings, and the ability to make better use of renewable energy contracts.”
Ore Energy’s pilot system — which uses iron, air, and water to store clean energy for up to 100 hours — was deployed at The Green Village, a living lab for next-generation climate and energy technologies located at Delft University of Technology (TU Delft).
The startup was spun out of TU Delft and maintains a close collaboration with the university. The nearby location allows for direct access and monitoring, while the site's microgrid setup provides ideal conditions for real-world testing and validation.
The installation is now collecting real-world operational data and will serve as a testbed for multi-day energy shifting, which is a key milestone on the way to full renewable grid integration.
Ore Energy’s full-scale system will use modular 40-foot containers, each delivering up to 4.2 MWh of multi-day energy storage, optimised for low-cost, low-footprint deployment.
“This achievement is proof that Europe can lead the world in energy innovation and energy resilience. We’ve shown that breakthrough solutions like iron-air can move from lab to grid in just two years and can be built entirely with a European supply chain,” said Yilmaz.
“Our battery doesn’t just store clean energy, it solves three of the grid’s biggest problems: it slashes curtailment, replaces fossil backup, and reduces the need to overbuild wind and solar.
Long-duration storage like ours is what makes renewable power reliable, affordable, and sovereign. And now it’s ready.”
“The Green Village exists to bring bold ideas out of the lab and into the real world. Ore Energy’s iron-air battery is exactly that kind of breakthrough,” said Lidewij van Trigt, Energy Transition Project Manager at The Green Village.
“Connecting the world’s first grid-ready iron-air system here in Delft shows what’s possible when research, regulation, and industry align. We’re proud to provide a proving ground for technologies that will shape the future of Europe’s energy system.”
Market maturity has finally arrived, but regulations need to catch up
According to Yilmaz, iron-air batteries require a multidisciplinary approach — chemistry, mechanical engineering, and grid integration.
“Until recently, the market wasn’t mature enough to support that kind of effort. But now, with the rise of wind and solar, the need for long-duration, low-cost storage is undeniable — and the conditions are finally right.”
The company plans to scale to 50 GWh/year by 2030. The company has set an ambitious goal of 50 GWh/year by 2030. To get to this, Yilmaz shared, “First, we need to scale up production rapidly. That’s already in motion.
!But we also need market mechanisms — tenders, incentives, recognition of long-duration storage in energy planning. If regulation catches up, and the market embraces this technology, 50 GW is realistic.”
According to Yilmaz, the technology is ready, but the regulatory environment for long-duration energy storage is still evolving. There’s no standardised way to value or procure LDES yet, and that slows down deployment.
“Things are improving, but policy support is essential to reach the scale we’re aiming for.”
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