Energy · Deep dive

Ore Energy

A TU Delft spinout building iron-air 'rust batteries' for multi-day storage — Europe's answer to Form Energy, betting that 100-hour storage at a tenth of lithium's cost can retire the gas peaker.

emerging

The question that decides it: Can a European iron-air entrant reach a bankable, warrantied round-trip cost per kWh at grid scale before Form Energy's US head start — and cheap LFP 8-hour systems plus sodium-ion — define the LDES procurement standard and leave nothing for 100-hour chemistry to win?

My take ★★ Very interesting ★ Interesting − Maybe ✗ Not interesting

Snapshot

Ore Energy is a TU Delft spinout building iron-air batteries — “rust batteries” — for long-duration energy storage, capable of discharging for up to 100 hours versus the four-to-twelve hours of grid lithium-ion. Founded in 2023 in Delft, it raised a $43M (€37.3M) Series A in August 2026 co-led by Plural and HV Capital, taking total funding to about $61M. It has connected what it says is the world’s first grid-connected iron-air system, run pilots with EDF, and signed a 1 GWh offtake with Dutch supplier Budget Thuis. It is, in effect, Europe’s answer to America’s Form Energy — but roughly a billion dollars and several years behind it. The whole thesis rests on one unproven claim: that storing energy for days, at a tenth of lithium’s cost per unit of capacity, can beat the gas peaker on price.

Founding story

The technology is older than the company. Iron-air chemistry was studied in the 1970s and 1980s, then largely abandoned because its round-trip efficiency was poor and lithium-ion eventually got cheap. What changed is the problem: a grid saturated with intermittent wind and solar now needs somewhere to put surplus power for days at a time, and lithium-ion — brilliant for four-hour arbitrage — is the wrong tool for a three-day wind lull.

Aytac Yilmaz spent about three years on the electrochemistry as a PhD and postdoctoral researcher at TU Delft, part of a research group that had been probing the fundamentals for years. His read was that the moment had arrived to bring iron-air back — not because the physics improved dramatically, but because the economics of the grid finally rewarded cheap, inefficient, long-duration storage. In 2023 he spun the work out with two co-founders from the same TU Delft orbit: Rutil Özdemir, now COO, and Yaiza Gonzalez Garcia, the materials scientist who serves as CSO. By their own account the founding team spent roughly eight years in and around TU Delft on this specific chemistry before commercialising it.

The pitch writes itself in a European accent. The materials are iron, water and air — abundant, cheap, non-flammable, and sourceable entirely within Europe, with no lithium or cobalt and no dependence on imported critical minerals or Chinese supply chains. That aligns neatly with the EU’s Clean Industrial Deal and made Ore an early European Innovation Council grantee. The company is a genuine deep-tech spinout, not a re-badged integrator — which is both its credibility and its risk.

How it works

An iron-air battery stores energy by rusting iron on purpose, then un-rusting it. During discharge, a metallic iron electrode sitting in a water-based (alkaline) electrolyte is oxidised — it rusts — and that reaction, in the presence of oxygen drawn in through an air electrode, releases electrons as current. To charge, you run electricity the other way: the rust is reduced back to metallic iron and oxygen is expelled. The cell literally “breathes” air in and out. Because the active material is essentially iron powder and the electrolyte is water, the bill of materials is dirt cheap and nothing in it burns.

The catch is efficiency. Iron-air round-trips at roughly 40-50% — for every 10 MWh you put in, you get 4-5 MWh back — against 85-90% for lithium-ion. That sounds disqualifying until you see the use case. If you charge with curtailed wind that would otherwise be paid to switch off (near-zero or negative marginal cost) and discharge across days when the alternative is burning gas, low efficiency is a rounding error against a fuel cost of roughly nothing. The economics live in cost per unit of capacity (dollars per kWh of storage), not in efficiency. Form Energy targets under $20/kWh; a six-hour lithium system runs closer to $150-180/kWh. Ore claims its systems cost roughly one-tenth of lithium-ion per unit of capacity.

Physically, Ore packages the technology into 40-foot containers rated at about 4.2 MWh each, configurable for durations from 24 to 100 hours, stacked to a customer’s need. The commercial argument is duration, not power: co-located with a wind farm, the containers soak up multi-day surpluses that a lithium fleet fills in its first two-to-four hours, and dispatch them when the wind dies.

Product and business overview

The core product is a containerised, modular iron-air LDES system — the 4.2 MWh 40-foot unit — sold to utilities, energy suppliers and, increasingly, developers who want firm, dispatchable renewable power. Ore describes its Delft pilot as the first LDES system fully designed, built and installed in Europe, and leans hard on that European supply chain as a differentiator against both US and Chinese competitors.

The target customers are concrete. First, European utilities decommissioning coal and gas plants who need something to fill the resulting multi-day gaps. Second, wind developers co-locating storage to cut curtailment and make better use of scarce grid-connection capacity — an acute pain point in the grid-constrained Netherlands. Third, and increasingly the headline, AI data centres: Ore’s fundraising narrative leans on data-centre electricity demand more than doubling to ~945 TWh by 2030, and on the idea that turning volatile renewables into firm baseload requires multi-day storage. That framing is as much investor catnip as it is engineering, but it is the story the round was raised on.

Business model and pricing

Ore has not published a price list — it is pre-revenue, with first commercial deliveries slated for 2028. The evident model is system sales (capex to the customer), likely evolving toward longer-term offtake or tolling-style arrangements as projects get financed. The Budget Thuis agreement is a deployment/offtake commitment rather than a disclosed-price sale.

What matters commercially is not a per-unit sticker but levelized cost of storage and, ultimately, bankability. Yilmaz is explicit that the metric is levelized cost of electricity and that the benchmark to beat is gas. The unstated hard part is warranties and financeability: to sell into utility procurement, Ore eventually needs a warrantied round-trip cost per kWh over a 20-year asset life that a lender will underwrite. No European iron-air player has demonstrated that yet, and neither, arguably, has Form. Until then, revenue is a function of grants, pilots and a handful of committed offtakes — not a repeatable sales motion.

Traction over time

The trajectory is real but early. As of mid-2025 the grid-connected battery was sub-megawatt-hour and most of the ~30-person team worked in R&D; headcount is now around 50. The Budget Thuis 1 GWh figure is a headline number, but the committed near-term slice is 400 MWh for 2028 — meaningful, still years out, and dependent on standing up manufacturing Ore does not yet have.

Market analysis

The addressable market is the >8-hour “storage gap” that today’s grid cannot economically fill. Market researchers size long-duration energy storage at roughly $4.8B in 2024-2025, growing to about $10.4B by 2030 (MarketsandMarkets, ~13.6% CAGR) and $17B+ by 2035 (SNS Insider). The bigger, more relevant numbers are physical: analysts at Virtue Market Research project 1.5-2.5 TW of LDES power and 85-140 TWh of energy capacity by 2040, implying $1.5-3T of cumulative investment; IDTechEx pegs the market at $223B by 2044. Whatever the exact figure, the direction is a step-change once renewable penetration passes the point where four-hour batteries stop being enough.

Two structural forces are pushing it. First, curtailment: Europe already wastes an estimated 72 TWh of renewable electricity a year — roughly Austria’s annual demand, worth nearly €7B at wholesale prices — because the grid cannot absorb or store it. Second, AI power demand: data-centre electricity use is set to more than double by 2030, and hyperscalers want firm, low-carbon power. Ore’s Europe-first supply chain is a genuine edge in a bloc obsessed with strategic autonomy and willing to subsidise domestic clean manufacturing.

The honest counterpoint: the >12-hour market barely exists commercially today. It is a bet on where the grid goes, not a market you can sell into at scale in 2026. And the same subsidies that could make Ore viable could evaporate with a political cycle.

Competitive intel

Form Energy is the elephant. Same chemistry, same 100-hour pitch, but $1.2B+ raised at a $3.42B valuation (Oct 2024), a producing factory in West Virginia, DOE backing and a project pipeline up to 8,500 MWh. Ore’s counter is geography and supply chain — Form is US-focused and IRA-shaped; Ore is European, EU-funded, and building where the grid constraints and coal phase-outs are acute. But Form has proven manufacturing Ore has not, and a head start measured in years and dollars.

ESS Inc is the warning. A US iron-flow LDES company that reached public markets and then nearly ran out of cash — revenue of $1.6M in 2025, a $63.4M loss, going-concern doubt. It is the clearest evidence that a compelling non-lithium thesis and real technology do not guarantee survival when deployment revenue arrives slower than the burn.

Invinity (vanadium flow) chases the same European utility RFPs with real installations but persistent losses and a costlier material. Lithium LFP and sodium-ion are the pragmatic threat from below: cheap, efficient, already stretching to eight hours, and improving. If buyers decide that stacking 8-hour LFP blocks plus a little gas is “good enough,” the 100-hour window may stay a niche. Thermal and mechanical players (Antora, Rondo, pumped hydro) attack multi-day firming from other directions. And gas — Yilmaz’s stated true rival — is the incumbent Ore must actually underprice.

History and evolution

• 1970s-80s: Iron-air studied for grid storage, then shelved as efficiency lagged and lithium-ion won on cost and round-trip.
• ~2015-2023: TU Delft research group revisits the chemistry; Yilmaz spends ~3 years on it as PhD/postdoc.
• 2023: Ore Energy spun out of TU Delft by Yilmaz, Özdemir and Gonzalez Garcia.
• May 2024: €10M seed (Positron Ventures) and exit from stealth.
• Jul 2025: First grid-connected iron-air system at TU Delft’s Green Village — a milestone, though the pilot cell is tiny (<1 MWh).
• 2025-26: EDF pilots; European Innovation Council support; grants lift total funding to ~€20M.
• Jun 2026: Budget Thuis 1 GWh agreement — its first supplier offtake and largest continental-Europe iron-air deal.
• Aug 2026: $43M Series A co-led by Plural and HV Capital, with Shell Ventures and Climentum joining; total ~$61M; ~50 staff; first factory the stated next step.

The stumbles are the ones inherent to deep-tech hardware: the flagship pilot is still sub-megawatt-hour, commercial revenue is years out, and the 50 GWh-by-2030 target is, by the company’s own business-development lead, “audacious” for a firm this size.

What people say

The case for. Investors and trade press credit Ore with combining world-class electrochemistry with unusually fast execution for a hardware startup. Plural’s Ian Hogarth argues iron-air is one of the biggest unsolved problems in the energy transition and that Ore could become “one of the world’s most important energy companies,” emphasising the export potential of a European-made technology. HV’s Maxi Pethö-Schramm ties the thesis directly to AI data centres and European industrial competitiveness. The Budget Thuis deal and EDF pilots are cited as evidence that serious utilities take the technology seriously, and the all-European, lithium-free supply chain resonates strongly with the EU’s strategic-autonomy agenda. Latitude Media flagged the grid connection as a real LDES benchmark.

The complaints. The skeptic case is well rehearsed and mostly comes from the same trade press. Tech Funding News called iron-air “an emerging and unproven category” and noted Ore’s battery has been grid-connected for less than a year, with a $43M round that is “modest by comparison” to peers. The recurring worries: round-trip efficiency of 40-50% is structurally low; the technology is unproven at commercial scale (Form’s own commercial-scale systems still have to demonstrate they work as promised); capital intensity is punishing, as Form’s $1.2B and ESS’s near-death both show; and whether iron-air can replace gas without permanent subsidy is genuinely open. The honest framing from observers is that the next five years — can it reliably and cost-effectively beat gas, or does it stay subsidy-dependent — will decide the whole category, not just Ore.

Outlook: the open question

Ore’s answer resolves on one thing: reaching a bankable, warrantied cost per kWh at grid scale before the market’s definition of “good enough” hardens around cheaper, faster-to-deploy alternatives. For that to break Ore’s way, three things must be true. First, the manufacturing has to materialise — first factory by 2028, then a credible path to gigawatt-hour-scale — because a spinout with a sub-megawatt-hour pilot and ~50 people is a very long way from 50 GWh a year. Second, the 400 MWh Budget Thuis first phase (and EDF work) must convert into financeable, warrantied projects that lenders will underwrite, proving the levelized-cost claim in the field rather than the deck. Third, the >12-hour storage market has to actually open, driven by renewable saturation and AI-firming demand, before LFP-plus-a-little-gas becomes the entrenched default.

For it to break the other way is easier to imagine. Form Energy is a billion dollars and a working factory ahead in the larger, better-subsidised US market. LFP keeps getting cheaper and longer; sodium-ion removes the lithium objection. ESS Inc is a live demonstration that the road from clever chemistry to cash-generating deployments can end in a going-concern warning. And Ore’s efficiency — 40-50% round-trip — leaves zero margin if curtailed power ever stops being nearly free. The technology is real and the European angle is genuinely differentiated; the $43M is not, on its own, enough to win a game Form is playing with $1.2B. The next raise, and whether it funds a factory that actually ships, will tell you more than any pilot has.

How a challenger would attack it

Skip the chemistry race and win the bankability race. Ore’s exposed flank is not its electrochemistry — it is the gap between a sub-megawatt-hour pilot and a warrantied, lender-underwritable 20-year asset, a gap it must cross with ~$61M against Form’s $1.2B. A challenger doesn’t need better iron-air; it needs faster financeability. The sharpest attack is a systems integrator that takes proven cells — stacked 8-hour LFP or arriving sodium-ion — and sells European utilities a “good enough” 24-48 hour product today, with bankable warranties from tier-one manufacturers, locking in the procurement standards before Ore’s 2028 first deliveries exist. Ore’s own competitor list concedes this: if buyers standardise on stacking LFP blocks, the >12-hour window never opens. Second vector: Form itself entering Europe — the strategic-autonomy story evaporates the day Form licenses European manufacturing or lands one EU gigafactory grant, because Form arrives with a producing factory and an 8,500 MWh pipeline as reference. Third: the offtake book. Budget Thuis’s committed slice is 400 MWh for 2028; a rival with capital can simply outbid for the handful of Dutch curtailment-heavy sites that make the first projects pencil, starving Ore of the reference deployments its Series B depends on.

Same playbook, new buyer

Sell the 40-50% round-trip machine where wasted power is guaranteed, not incidental. Ore’s economics only work when charging power is nearly free — which makes the best buyer not a Dutch utility navigating merchant curtailment, but anyone structurally drowning in stranded generation. Three shifts stand out. Island and off-grid systems — Mediterranean islands, African mini-grids, remote mining operations — burn diesel at costs no gas peaker in Europe approaches, so the levelized-cost bar Ore must clear drops dramatically and the competition is a generator, not the EU procurement machine. Second, co-location with curtailment-contracted wind in Iberia and the North Sea, sold to the developer as a curtailment-recovery product rather than to the grid as storage — Europe’s 72 TWh of annually wasted renewables is the feedstock, and the buyer already owns it. Third, the data-centre firming story Ore uses as fundraising narrative could be an actual first market for a competitor willing to sign behind-the-meter deals with hyperscalers at premium pricing. Ore won’t pivot to any of these easily: its roadmap, grants and supply-chain story are wired to EU grid infrastructure and the 2035 “standard European LDES” goal, and a 50-person pre-revenue company standing up its first factory cannot chase three markets at once.

Sources and further reading

• Tech Funding News — “Dutch iron-air battery startup Ore Energy secures $43M from Plural and HV Capital” (Sofia Chesnokova, 4 Aug 2026)
• EU-Startups — “Ore Energy raises €37.3 million to scale iron-air batteries…” (Rahul Raj, 4 Aug 2026)
• Latitude Media — “In a first, Ore Energy just hooked up an iron-air battery to the Dutch grid” (Lisa Martine Jenkins, 30 Jul 2025)
• Energy-Storage.news — “Ore Energy signs 1GWh iron-air battery deal with Dutch utility” (24 Jun 2026)
• The Engineer — “Ore Energy raises $43m for iron-air battery tech” (Aug 2026)
• Canary Media — “Form Energy raises $405M for its 100-hour iron-air batteries” (Oct 2024)
• Energy-Storage.news — “Iron flow battery maker ESS Inc warns of survival battle through ‘operational reset’” (2025)
• MarketsandMarkets — “Long Duration Energy Storage Market worth $10.43 billion by 2030” (2025)
• TU Delft — “Strike when the iron is hot: why Ore Energy believes in bringing back iron-air batteries” (2025)