The Deal That's Turning Heads
Ore Energy, a Netherlands-based long-duration energy storage startup, announced a landmark agreement with Dutch energy supplier Budget Thuis to deploy 1 gigawatt-hour of iron-air battery storage — the largest such deal on the European continent to date. The first phase, totalling 400 megawatt-hours, is scheduled for delivery in 2028.
For context: 1 GWh of storage is enough to power roughly 1,000 average European homes continuously for an entire year. But grid storage doesn't work like that — what matters is how long a battery can hold its charge and release it smoothly during the periods when wind and solar aren't generating. That's exactly where iron-air technology shines.
Budget Thuis CEO Annemarie Buitelaar framed the deal in plain terms: the goal is "reducing exposure to volatile fossil fuel prices while giving customers access to cleaner electricity." For a utility competing in the Dutch retail energy market, that is both a business strategy and a customer promise.
How Does a Battery Run for Four Days?
Iron-air batteries work on a surprisingly elegant principle. During charging, electricity reverses rust — converting iron oxide back to pure iron metal. During discharge, the iron reacts with oxygen from the surrounding air, releasing stored energy as it oxidises back into rust. The cycle repeats. The materials involved: iron, water, and air. Nothing more.
This simplicity is not a compromise — it is the point. Unlike lithium-ion cells, which need cobalt, nickel, manganese, or lithium sourced primarily from outside Europe, iron-air systems can draw entirely from European supply chains. Iron is one of the most abundant elements on Earth. Air is free. Water is local.
The trade-off is real: iron-air batteries are bulkier and less energy-dense than lithium-ion alternatives. They also lose more energy in the conversion process, making them less efficient for short-cycle applications like electric vehicle batteries or intra-day grid balancing. But when the job is storing energy across 72 to 100 hours — spanning cloudy, windless days — the economics shift decisively in iron-air's favour.
Ore Energy's units ship in modular 40-foot containers, designed to be stacked and scaled at grid-connected sites without complex infrastructure requirements.
Europe's Grid Has a Problem Iron Can Solve
The urgency behind this deal is easy to understand once you look at how European grids are actually behaving. Across the continent, renewable capacity has grown faster than the infrastructure needed to store and distribute it. The result is curtailment — grid operators are increasingly forced to switch off wind turbines and solar farms simply because there is nowhere to send the electricity they are generating.
Ore Energy CEO Aytaç Yilmaz put it directly: "European grids are already curtailing clean power at scale. Short-duration batteries alone can't fix this. They shift solar by a few hours, but wind-heavy European grids need storage that works across days, not hours."
The Netherlands is a particularly clear example of this tension. It has ambitious offshore wind expansion targets but a transmission grid that struggles to absorb large swings in generation. During periods of high wind and low demand, power prices can turn negative. During calm winter weeks, gas plants run at full capacity. Multi-day storage could smooth both extremes.
Proven in the Field: The EDF Pilot
Ore Energy isn't arriving with only laboratory data. Between August and November 2025, the company completed a grid-connected pilot with French energy giant EDF, successfully demonstrating four-day continuous storage under real operational conditions. It was the first grid-connected iron-air pilot in Europe.
That proof of concept matters enormously for utility buyers. Budget Thuis and future European partners are not betting on a concept — they are scaling a system that has already run on an actual grid, connected to actual transmission infrastructure, in actual weather.
Why This Matters Beyond the Netherlands
The implications extend well beyond one Dutch utility's portfolio strategy. Europe's 2030 and 2050 climate commitments require massive buildout of renewable generation — but generation alone is not enough. Renewable energy must be dispatchable: available when needed, not only when the wind blows or the sun shines. Long-duration storage is the missing link that makes variable renewables reliable.
For EV drivers, this has practical consequences. Charging infrastructure connected to grids dominated by renewable energy is only as clean as the grid's ability to store and deliver that energy on demand. Iron-air systems that buffer days' worth of clean power make overnight charging genuinely low-carbon regardless of weather conditions. They also stabilise electricity prices by reducing reliance on gas peaker plants during periods of low renewable output — which means cheaper charging costs in the long run.
European energy policy has begun to acknowledge the long-duration storage gap. The EU's Net-Zero Industry Act and various national grid development plans increasingly reference multi-day storage as a strategic priority — but until now, commercial-scale deployments have been scarce. The Ore Energy–Budget Thuis deal may mark the point where ambition and commercially available hardware finally converge.
The Bigger Competitive Picture
Ore Energy is not alone in this space. US firm Form Energy, backed by ArcelorMittal and Google, has been developing iron-air technology for grid deployments in North America. The European market has lagged behind, partly due to different grid structures and partly due to a procurement culture that favoured established lithium-ion suppliers.
What Ore Energy brings is a European identity — founded in the Netherlands, drawing on European supply chains, and clearly targeting the EU market first. In a policy environment increasingly focused on energy sovereignty and reducing dependence on external supply chains for critical technologies, that positioning is a genuine advantage.
The 2028 delivery timeline for the first 400 MWh phase is tight but achievable. If the rollout proceeds on schedule, the Netherlands could have the largest operational iron-air installation in Europe before the end of the decade — and a template other utilities will study closely.
How does an iron-air battery actually work?
Iron-air batteries store energy through a reversible chemical process called rust. During charging, electricity converts iron oxide (rust) back into pure iron metal. During discharge, the iron reacts with oxygen from the air, rusting again and releasing stored electricity. The process can repeat thousands of times, using only iron, water, and air — no rare or imported minerals required.
Why can't we just use more lithium-ion batteries for long-duration storage?
Lithium-ion batteries are highly efficient for short-duration storage — typically 2 to 8 hours — but become extremely expensive when scaled to store energy for multiple days. Their chemistry also degrades more quickly under deep, prolonged discharge cycles. Iron-air batteries are less energy-dense but far cheaper per kilowatt-hour at long storage durations, making them economically suited for 50–100 hour applications that lithium-ion simply cannot match at grid scale.
When will the Budget Thuis iron-air storage come online?
According to Ore Energy, the first phase of the deal — 400 megawatt-hours — is scheduled for delivery in 2028. The full 1 gigawatt-hour commitment will follow in subsequent phases, subject to permitting and grid connection timelines in the Netherlands.
Source: https://electrek.co/2026/06/22/europe-is-betting-big-on-a-battery-that-runs-for-four-days/