The race to commercialize the long-duration energy storage systems colloquially known as “100-hour batteries” is accelerating.
Earlier this month, Dutch startup Ore Energy announced it had wrapped up a pilot project with French utility EDF, during which one of its iron-air long-duration energy storage systems operated while connected to the grid near Paris for three months.
The news comes some six months after the company completed its first pilot project, and just a couple of weeks after U.S. competitor Noon Energy announced it had also successfully operated its own carbon-oxygen 100-hour battery for multiple months, on the other side of the Atlantic Ocean.
These companies are small, but these technical milestones are signs of maturity for a market that has so far been dominated by the well-capitalized iron-air battery developer Form Energy. The company has raised over $1.2 billion so far and is reportedly raising another $300 million to $500 million financing round before it plans to go public next year.
Just last fall, Form began deploying its first commercial batteries, right as it simultaneously began fielding more near-term demand than it planned for, largely as a result of the artificial intelligence boom — which is another element nudging the broader market toward maturity. Eos Energy, for example, which makes a long-duration zinc-based battery, told Latitude Media that it saw its pipeline grow by more than 50% because of an unexpected surge in demand by data center customers — and that was in July 2024, when the AI infrastructure boom was still in its early stages.
Long-duration energy storage technologies can discharge electricity for multiple days at a time, and therefore can fill the days-long renewable supply gaps when the wind isn’t blowing, and the sky is overcast. When paired with a grid connection, LDES can act almost like baseload power, which could be especially useful when it comes to meeting the energy and flexibility needs of the booming data center industry.
At least, that’s the theory. The process of actually getting these technologies to market has been a long and winding one, but it seems that we may be approaching the final stretch.
For more on the applications of a 100-hour battery, listen to Form Energy CEO Mateo Jaramillo’s interview on the Catalyst podcast:
Bas Kil, who leads Ore Energy’s business development, told Latitude Media that in the months since he started working for the company in March of last year, the market acknowledgement and understanding of the need for long-duration energy storage have only grown. Especially in Northwestern European markets with high wind capacity, Kil said, “business models for renewables are difficult right now,” he said, referring to regions with high wind capacity where utilities frequently see energy prices turn negative for prolonged, financially damaging periods.
“We’re sort of running up against the limits of how many renewables can be integrated within the energy system without the business model collapsing,” he said. “We’re seeing offshore wind tenders that are no longer successful, and signals from [transmission system operators] that grid reliability is not going to be guaranteed anymore. So there’s a really strong understanding that longer flexibility within the system is needed.”
In the U.S. specifically, both short- and long-duration storage companies were unexpectedly propelled by the continuation of tax incentives in the GOP’s One Big Beautiful Bill last summer. While many renewables incentives were slashed, storage received a surprise reprieve; LDES technologies are eligible for the technology-neutral 48E credit. Meanwhile, green hydrogen, which until recently was widely considered the long-duration storage solution to complement lithium-ion’s short-term performance, has not evolved as quickly as the industry originally hoped, Kil said. (Green hydrogen tax credits were largely preserved by OBBB, which extended the 45V “commence construction” deadline through January 2028.)
“Green hydrogen’s cost is not going to go down as expected, and using electricity to produce green hydrogen and then using it again to make electricity is extremely inefficient,” Kil said. “So, the technology that we thought was going to be the solution is not really there anymore, and there’s a need being recognized.”
Towards manufacturing
Each LDES company is taking its own approach to the technology. While Noon Energy utilizes a reversible solid oxide fuel cell that cycles carbon and oxygen to store electricity, Ore’s system relies on a reversible rusting process, which is similar to the iron-air approach pioneered by Form Energy.
During this latest pilot, Ore connected one of its systems, which is housed in a 20-foot container with a capacity of just under one megawatt-hour, to the grid at an EDF facility near Paris. The system underwent various testing phases: “We did accelerated charging and discharging for 24 hours to do some testing around shorter storage duration, because we do believe there’s a progressive need for longer storage,” Kil said, noting that Ore also simulated wind-colocation scenarios.
Compared to the company’s first pilot — which was located at a grid-connected university technology testbed in the Netherlands — this project focused on streamlining operations and optimizing the stacking of cells within the system. These improvements are critical for the next key commercialization step: manufacturing as cost-effectively as possible. Ore is targeting a product that is as much as 10 times cheaper than lithium-ion, a difficult feat in a market where lithium-ion system prices have been decreasing.
“We are now in the process of scaling up our manufacturing capabilities, so we are raising funding to build our first-of-a-kind factory,” Kil said. “The goal now is to put down our first manufacturing line and start producing batteries at a larger scale.”
This will require crossing the proverbial Valley of Death between the lab and commercialization, which is a delicate, time-consuming, and expensive process — even for a cash-flush company like Form, which has spent the last several years “becoming a manufacturing company” as CEO Mateo Jaramillo told Latitude Media last fall. While the latter has raised over $1 billion, has secured over $1.2 billion to date, Ore Energy is starting the process with a leaner $23.5 million in capital as of February 2026. Noon Energy has raised over $50 million in venture capital and government grants.
And it will also require expanding the company’s staff significantly. Form Energy has hundreds of employees, whereas Ore and Noon both number in the dozens.
That said, Kil says Ore expected its first manufacturing facility to be operational in 2027. The company is currently evaluating existing factories that could be converted in Germany and the Netherlands, to avoid having to build a facility from scratch.
“It’s not going to be immediately the massive scale that we hope to reach,” Kil said. “But we’re doing this in steps, right?”
Editor’s note: This story was updated on February 19 to correct the amount of money Ore Energy has raised. The company has raised roughly $23.5 million so far, not $13.5 million, as an earlier version of the story stated.
