Long-duration energy storage startup Ore Energy has signed what it calls the largest iron-air battery agreement in Continental Europe to date, then topped it with fresh venture money. The Netherlands-based company will supply Dutch energy retailer Budget Thuis with 1 gigawatt-hour (GWh) of iron-air storage, beginning with a committed 400-megawatt-hour (MWh) first phase slated for 2028. Days later it confirmed a $43 million Series A round led by the European VC Plural, taking its total raised past $61 million.
The funding lets Ore set up its first manufacturing line, a step toward gigawatt-hour-scale output in 2028. The Budget Thuis partnership matters beyond its size. It is the first iron-air storage agreement signed with a European energy supplier, and one of the clearest signs yet that a chemistry long dismissed as too bulky to matter is gaining real traction.
Why utilities want storage that lasts for days
The bet rests on a plain problem in modern power grids. As wind and solar penetration climbs, generation no longer lines up with demand. Wind tends to blow hardest at night, when usage is low, and solar peaks at midday while consumption spikes in the evening. Grid operators are forced to switch off clean generation they cannot use, a practice known as curtailment, and to lean on gas plants to cover the gaps.
Lithium-ion batteries solve a slice of that puzzle. They discharge quickly, over four to eight hours, which makes them ideal for smoothing the evening peak or soaking up a midday burst of sun. They are far less useful when the wind goes quiet for two or three days straight. That longer window is where iron-air chemistry enters.
Ore batteries can hold electricity for up to 100 hours, roughly four days, against the usual four-to-eight-hour window of a lithium bank. The technology runs on iron, water, and air. Inside each cell, iron combines with oxygen pulled from ambient air during discharge, and the charge step reverses that reaction. The hardware ships in modular 40-foot containers that can be chained to scale capacity, and the company says configurations can run anywhere from 24 to 100 hours of storage duration.
The trade-offs are real. Iron-air systems are heavier and less efficient than lithium-ion, losing more energy in the round trip. But for a giant grid asset meant to hold cheap wind power for days at a time, density matters less than cost. The core materials are cheap and abundant, and Ore says that keeps its supply chain inside Europe and dodges much of the critical-mineral exposure that comes with conventional battery chemistry.
Why European grids have been cutting wind generation
Long-duration storage is arriving during an awkward stretch for European renewables. Several markets have curtailed clean power at scale over the past few years, a pattern the industry says is wasting electricity worth billions to generate.
Ore cofounder and chief executive Aytaç Yilmaz framed the problem directly. He said European grids keep trimming clean power at scale while staying dependent on fossil fuel to cover gaps, and argued that short-duration batteries alone cannot fix it. They only shift solar by a few hours, he said, while wind-heavy grids need storage that works across days rather than hours.
For Budget Thuis, the pitch is easy to state: hold excess wind power when it is plentiful and sell it back to the grid during stretches when renewable output sags and wholesale prices climb. Chief executive Annemarie Buitelaar said the aim was to reduce exposure to volatile fossil-fuel prices while handing customers steadier, cleaner electricity over time. She pointed to Ore's prior deployments as proof the pair could deliver, which is why the utility was committing a full GWh across its portfolio, starting with the first 400 MWh phase in the Netherlands.
The trials behind the order
The confidence draws on live tests. In February this year Ore said it had wrapped a pilot with EDF in France, which it described as the first grid-connected iron-air long-duration storage unit in Europe. That project ran between August and November 2025 and delivered up to four days of energy storage under real utility conditions.
Before that, Ore had installed a grid-connected unit in Delft, in the Netherlands, to check whether the hardware could hold together against existing European grid infrastructure. Those two runs, plus the new commercial contract, hand the startup something rare in the long-duration-storage world: a working product with a named customer behind it.
The funding round backs the story. Plural led the $43 million raise, and Ore now sits past $61 million raised to date. The injection is meant to pay for the company's first manufacturing site ahead of its 2028 production goals.
The economics of a battery that cycles slowly
Skeptics point out the business case is a puzzle. A long-hold cell does not cycle often, and a battery only makes money when it turns over, since each full cycle is a further unit of revenue. A 1 GWh unit that discharges over 100 hours delivers, on paper, around 10 MW of sustained output, a slow trickle. For the math to work, that capacity has to stay cheap to build, which is where iron and water come in.
The iron-air development echoes a broader economics argument that has powered many grid-storage announcements lately. Producers say storage is no longer an environmental footnote but a business line in its own right. A system that shifts a few hours of evening demand commands a different price than one that can cover a full day or more, and the revenue split is increasingly what decides whether financiers back a project.
How ore saturation changes the grid picture
Grid operators in Europe are watching the longer-duration market closely because the numbers are starting to shift. Where storage once worked mainly as a peaker-hours tool, the spreading of cheap wind and solar across the day is pushing more of the economics into the multi-day slot. Analysts who follow the sector say the real challenge is not building a battery that holds energy but making one whose build cost is low enough that a few slow cycles pay for it.
Ore's answer to that loading problem is a deliberate trade. By giving up power density and accepting a slower discharge, the company cuts the cost of the active chemistry to a handful of ordinary elements. The founder's point, that a lot of the European grid's problem is that wholesale prices sit at zero or negative for hours at a time, leans on the fact that a cheap tank of iron and air does not care whether it cycles once a day or once a week.
Where long-duration storage fits in Europe
The budget math matters because iron-air enters at the low end of the cost curve. Long-duration chemistry has to price itself below the cost of keeping a gas plant standing by, or it never gets dispatched. Backers of iron-air point to the simple materials list as the reason the units can hit that floor, even when efficiency trails lithium.
The announcement lands as European battery builders race to reassure markets that supply chains can be rebuilt close to home.
What the announcement means for the market
Ore's roadmap now moves on two rails: the Budget Thuis commitment in the Netherlands and the scaling of manufacturing. A 2028 target for gigawatt-hour output would push iron-air into a league that many skeptics once guarded for lithium. If the Dutch utility's first 400 MWh phase lands on time and holds up, iron-air will get one of its clearest test cases yet.
For European grid operators, longer-duration storage may prove the difference between a renewable system that keeps gas plants warm as a backup and one that can trust storage to carry a multi-day gap. The economics are far from settled, the chemistry is unglamorous, and the scale-up will move far slower than a lithium gigafactory. But a utility has put real money on it, which is more than most rival chem tech can claim today.
Ore's turn into the multi-day niche sits alongside other battery research across the wider battery industry. For now, the largest iron-air deal in Continental Europe and a fresh round of funding give long-duration storage a louder voice in the running debate about what a fully renewable grid actually needs. The next test is playing out in the Netherlands in front of the whole market.