Elestor discusses its decision to move from hydrogen-bromine to hydrogen-iron flow batteries, highlighting the necessity of technology acceptance, societal support and regulatory compliance, alongside sustainability, scientific progress and economic viability.
The hugely complex and yet extremely simple idea that a technology must be permissible in order to succeed was a key reason behind Dutch long-duration electricity storage company Elestor’s decision to officially transition from hydrogen-bromine to a hydrogen-iron chemistry.
Probing a new technology’s permissibility is a form of unscientific stress-testing that is performed in the real world. As a process, it is invariably messier and less predictable than testing in laboratories.
“It’s one thing to be convinced you’re on the right track; that you’re doing the right thing; that your solution is the best thing since sliced bread,” reflects Joep Lauret, Elestor’s project and compliance manager. “It’s quite another to persuade others that you’re right.”
Obstacles range from formal directives and regulations to informal arguments motivated by emotions and subjective opinions, as well as varying degrees of insight and prejudices.
“The real world is less rational, filled as it is with hidden and at times baffling agendas,” Lauret observes. “As such, it is arguably even more complex than science could ever be. There are good reasons why so many genius scientists shelter in the lab.”
Approval by fellow scientists means everything in academia, which is governed by transparency and peer reviews. The views of peers matter in the real world too, though they often need rephrasing to appease lawyers, regulators and policy makers.
But when it comes to persuading the general public, the scientists’ views often carry no more weight than pre-held ideas, misunderstandings, long-held prejudices and more or less irrational concerns.
“In spite of this, we must always remember two fundamental truths. The societal stakeholders don’t have a duty to be well informed, but they nevertheless have a right to be heard,” Lauret notes. “And heard they will be, by policy makers and regulators, by the media and by each other, so it is essential that we secure the backing of ordinary people.”
Elestor has found it easy to persuade politicians and local communities, including representatives from the emergency services, that a hydrogen-iron flow battery would be a perfectly acceptable neighbour.
Dutch long-duration electricity storage company Elestor recently announced that it is officially transitioning from hydrogen-bromine to a hydrogen-iron chemistry, marking a significant step forward for large-scale, long-duration energy storage.
The decision was based on a complex and wide range of criteria, having evolved naturally after years of research and development, extensive testing, and deep consultation with both commercial partners and the company’s international council of scientists and engineers.
The shift to a hydrogen-iron chemistry is driven not only by scientific advances but also by real-world economic and market realities, regulatory compliance considerations, and the growing need for resilience in an increasingly complex world.
“Recent geopolitical turbulence has made energy security, regional resilience, and independence from hostile regimes more critical than ever,” says Hylke van Bennekom, CEO, Elestor.
“This was not quite as easy when it came to hydrogen-bromine flow batteries,” Lauret explains, “and this was one of the main reasons why Elestor chose to switch to a new chemistry.”
Additional reasons why Elestor transitioned from hydrogen-bromine to a hydrogen-iron chemistry will be explored in future issues of Innovation News Network.
Hydrogen-iron permissibility: formal and informal requirements
The permissibility of Elestor’s Hydrogen-Iron batteries is reliant on both formal and informal factors. The formal ones are complex but straightforward to deal with, as the requirements are spelt out in detail by regulators and certification professionals. The informal ones deal with many additional factors, including subjective opinions.
Hydrogen-iron compliance
The most basic formal requirements are compliance with all relevant regulations and directives. A key criterion during the development of Elestor’s hydrogen-iron battery is its full alignment with a number of EU directives, most notably the EU Battery Regulation (EU 2023/1542). This regulation is particularly relevant as Elestor’s system includes platinum-based catalysts, which are classified as critical raw materials.
Elestor supports transparent sourcing and responsible use, and is prepared to meet obligations such as digital battery passports, carbon footprint declarations, and extended producer responsibility as the regulations are phased in. In addition, Elestor’s hydrogen-iron flow battery complies with the Machine Regulation (2023/1230), the Low Voltage Directive (2014/35/EU), the EMC Directive (2014/30/EU), the Pressure Equipment Directive (2014/68/EU), the ATEX Directive (2014/34/EU), and the Cyber Resilience Act (EU Regulation 2024/1093), which ensures the company’s products are secure by design. Together with the adherence to relevant social and environmental directives, the batteries are designed to be compliant throughout the product lifecycle.
Together, these frameworks ensure safety, environmental stewardship, interoperability, and long-term product value. In addition to the EU-level regulations, individual countries usually impose national requirements, such as construction permitting, fire safety, or environmental protection.
Elestor plans to approach local compliance on a project-by-project basis. The company is already working with authorities and stakeholders, such as the Dutch Institute for Public Safety (NIPV), representatives of the environmental services, fire brigades and municipalities in the Netherlands. In addition, Elestor has received input from Germany and Norway, and works closely with authorities to ensure all national and local legal requirements, norms and guidelines are met. This approach enables a flexible and seamless deployment across a wide range of use cases and geographies. Insurers also agree that Elestor has reduced operational risk with its new electrolyte, which in turn also reduces insurance costs.
Hydrogen-iron permittability
Somewhat less formal, or at least often more subjective, requirements relate to the battery’s permittability, which is all about how easy it is to get permissions and secure permits to install and operate a battery.
A hydrogen-iron flow battery uses chemicals that are neither poisonous nor toxic, nor do they have corrosive fumes. This is a major advantage when it comes to public safety, and as such, it is easier to secure permits for this chemistry than for some other so-called redox couples.
The much lower liquid corrosivity also removes the need for so-called ‘forever plastics’ to contain the chemicals, which in turn makes the total system more sustainable and thus more permittable.
The hydrogen and the acidic electrolyte in Elestor’s hydrogen-iron flow battery can also be stored and contained according to existing industry practices. The industry has a very good track record in this regard. Consequently, the risks of any incidents, such as a leak, are very low. In addition, it is important to realise that if such an unlikely scenario were to materialise, any harmful effects would be minimal as no harmful vapours would arise.
Hydrogen-iron value propositions
Elestor’s hydrogen-iron flow battery has several additional value propositions. These are some of them:
- They are land-based stationary systems, which means there is no need to store the hydrogen at high pressure in order to reduce its volume.
In contrast to hydrogen mobility solutions, which often work at 300 or 700 barg, or typical hydrogen pipelines that might work on 60 barg, the Elestor battery is designed to work on relatively low hydrogen pressures, varying from near atmospheric pressures towards maximum storage pressures of 16-20 barg either in atmospheric double membrane domes or in pressurised metal tanks. Low pressures are easier to handle, they are safer, and they do not require very expensive equipment or materials.
Indeed, even if a leakage were to occur, the leak rates would be relatively small. Such storage facilities are well known in the industry and have a good track record. Hence, although hydrogen is flammable when mixed with air and potentially explosive, the risk with the Elestor battery is very low as the hydrogen is retained within a closed loop system without air. As opposed to water electrolysers that also produce oxygen, there is no similar risk that oxygen also enters the hydrogen circuit.
- Elestor’s hydrogen-iron flow battery uses a liquid electrolyte, which is acidic but not poisonous. It does not vapourise harmful gases in the event of an accidental release. Good industry practices for storage and construction can be applied and combined with recognised engineering standards to guarantee that risks are kept very low.
- As was the case with Elestor’s previous chemistry, the physical locations of power generation and energy storage are separated in its hydrogen-iron flow battery system. Hence, even in the extremely unlikely event of a fire on the power generation side, a separator valve would shut down the source of fuel (hydrogen).
Hence, any fire can be put out quickly by an automated fire extinguishing system. This setup is highly appreciated by authorities that oversee public safety, such as the fire brigade or local and national safety institutes.
- At very large sizes, any energy system is likely to be subject to the Seveso Directive, which forms a key part of the EU’s commitment to environmental and public safety. This directive aims to prevent major industrial accidents involving dangerous substances and to limit their consequences for human health and the environment. The Seveso Directive is applied through a combination of strict regulatory measures, reporting requirements and safety protocols.
Facilities are categorised into lower-tier and upper-tier, based on the quantity of hazardous substances they handle. Each category has specific requirements for safety measures and reporting.
Logically, it is more difficult to get permits for systems that need to comply with Seveso requirements. Very large hydrogen-iron flow batteries can be built before the Seveso requirements apply; hence, it is much easier to get permits for their installation and operation.
Please note, this article will also appear in the 22nd edition of our quarterly publication.
