Elestor

What Elestor does

Elestor B.V. is a Dutch private company founded in 2014 in Arnhem, Netherlands, that develops hydrogen-iron (H2-Fe) flow battery systems for grid-scale, long-duration energy storage. The technology stores energy using hydrogen gas at the anode and an aqueous iron-salt electrolyte at the cathode, separated by a proprietary proton-conductive membrane, with the electrochemical stack sized for power (MW) and external tanks sized independently for capacity (MWh). The company originally developed hydrogen-bromine chemistry but transitioned to hydrogen-iron to improve safety, eliminate toxic substances, and raise Seveso directive thresholds that govern single-site storage size. Elestor targets storage durations of 8 to 150 hours, a band where lithium-ion is economically disadvantaged, and reports a target CAPEX of approximately €15/kWh, levelized cost of storage of approximately €0.02/kWh, round-trip efficiency above 75%, and a 20-25 year operational lifetime with stable 80%+ efficiency over tens of thousands of cycles.

The business model is direct enterprise sales of large-scale battery systems to utilities and grid operators, industrial and commercial enterprises, renewable energy developers, islands and remote locations, and data centers, priced per kW and kWh via multi-year, quote-based contracts. The company operates from a single headquarters at Industriepark Kleefse Waard in Arnhem and is currently constructing a pilot factory targeting 1 GW annual production capacity by 2026. As of January 2024, Elestor employed 55 staff, had raised approximately €30 million in a Series A round led by Equinor Ventures with Invest-NL as co-lead, secured a €22 million Dutch National Growth Fund subsidy via the SLDBatt consortium, and held a Joint Development Agreement with Royal Vopak. Named commercial deployments to date consist primarily of the 2018 ITMGroup installation at Kampen; revenue is not disclosed and the company is in a pre-commercial scaling phase.

Name

Elestor

Legal name

Elestor B.V.

Website

https://elestor.com

Company type

Private

Founded year

2014

Operating status

Operating

Headcount range

11–50 employees

Short description

Elestor develops hydrogen-iron flow battery systems for grid-scale, long-duration energy storage (8-150 hours), selling directly to utilities, industrial customers, renewable developers, and data centers in Europe.

Ownership category

akta.pro rank

Product category

Long-Duration Energy Storage Systems

NAICS

Battery Manufacturing (33591), Turbine and Turbine Generator Set Units Manufacturing (333611)

SIC

Engines & Turbines (3510)

akta.pro primary industry

Electrochemical LDES (Flow Batteries & Other Long-Duration Batteries) (EUAFADAA)

akta.pro secondary industries

Energy Storage Systems (BESS, Flywheels, Batteries) (HDABAKAC), UPS Batteries & Energy Storage Modules (HDACAJAE)

Keywords

• Long-duration energy storage
• Hydrogen-iron flow battery
• Grid-scale battery systems
• Renewable energy storage
• Flow battery technology

Headquarters

HQ city

Arnhem

HQ country

Netherlands

HQ region

Europe

Offices1 record

Markets served

GTM type

B2B

Offering type

Hardware or Manufacturing

Cost components

Technology or R&D, Personnel, Supply Chain, Infrastructure, Operations

Revenue model

1. Large-Scale Flow Battery Systems: Sale of hydrogen-iron flow battery systems for industrial-scale long-duration energy storage applications. Systems are sold directly to utilities, grid operators, industrial companies, and renewable energy developers.

Pricing tiers

Go-to-market motion1 record

Distribution channels1 record

Marketing channels6 records

Core offering

Elestor designs, develops, and sells large-scale hydrogen-iron (H2-Fe) flow battery systems for long-duration energy storage at the MW/MWh scale. The systems use hydrogen gas and dissolved iron salts as abundant, low-cost active materials, with independently scalable power and energy capacity, targeting durations of 8–150 hours and replacement of gas-fired backup power plants for utilities, grid operators, and industrial off-takers.

Product overview

Elestor offers a single core product line: its hydrogen-iron flow battery technology for large-scale, long-duration energy storage. The company originally developed hydrogen-bromine flow batteries but transitioned to hydrogen-iron chemistry for improved safety, reduced regulatory burden, and elimination of toxic substances. The flow battery architecture physically separates power generation (determined by electrochemical cell/membrane stack) from energy capacity (determined by external electrolyte and hydrogen tank volumes), enabling independent scaling. This design allows storage durations from 8 hours to 150+ hours by simply adding larger tanks, without requiring additional power infrastructure. The technology serves as a bi-directional power plant alternative to gas-fired backup generation, targeting grid operators, renewable energy producers, and industrial facilities requiring reliable long-term electricity storage.

Differentiator

Problem solved

Functional benefit

Products and services

• Hydrogen-Iron (H2-Fe) Flow Battery System Elestor's current core product: a large-scale, long-duration flow battery using hydrogen gas and dissolved iron salts (FeSO4) as active materials, with a proton-conductive membrane separating the anode and cathode. Power (MW) and energy (MWh) scale independently. Designed for 8–150+ hour storage durations, target CAPEX of approximately €15/kWh, LCoS near €0.02/kWh, round-trip efficiency above 75%, and 20–25 year operational life. Sold to utilities, grid operators, industrial users, renewable developers, and data centers.
• Hydrogen-Bromine (HBr) Flow Battery System Elestor's earlier flow battery product using hydrogen and bromine as active materials. Successfully deployed commercially at ITMGroup's Kampen facility. Elestor has transitioned away from this chemistry to hydrogen-iron for improved safety, reduced regulatory burden, and elimination of corrosive and toxic substances, so this product is no longer the active commercial offering.

Quantifiable outcome

• Capital costs of approximately €15/kWh at scale
• +7 more outcomes

Named customers1 record

Segments5 records

Ideal customer profiles5 records

Technology focussed Yes

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Feature8 records

Partnerships

15 partnerships are on record, tiered flagship, core and supporting.

• Royal VopakflagshipStrategic or Co-development Partner · 1 April 2021Entered Joint Development Agreement (JDA) in April 2021 with world's leading independent tank storage company. Jointly developing technology to industrial scale (10s of MW and 100s of MWh). Vopak is also an investor. Their seaport terminals provide optimal infrastructure for flow batteries.
• ITMGroupflagshipImplementation/ SI/ Consulting PartnerFirst commercial deployment of Elestor's HBr flow battery at Kampen facility in May 2018. ITMGroup serves as pioneering customer demonstrating the technology's commercial viability.
• Battery Competence Cluster NL (BCC-NL)coreStrategic or Co-development PartnerCoordinating the €22 million SLDBatt project. Acts as national catalyst for connection, knowledge sharing, and acceleration within the battery value chain.
• University of TwentecoreTechnology or IntegrationAcademic partner in SLDBatt consortium. Main applicant Guido Mul leads the project. Contributes to technology development and implementation scenarios.
• TU DelftcoreTechnology or IntegrationTechnical university partner in SLDBatt consortium. Professor Simon Watson served on Offshore Wind Innovators jury. Cooperates on European ecosystem development.
• TU EindhovencoreTechnology or IntegrationTechnical university partner in SLDBatt consortium. Joint research on membrane materials and processes for hydrogen-bromine flow batteries.
• Hogeschool van Arnhem en Nijmegen (HAN)supportingTechnology or IntegrationUniversity of applied sciences partner in multiple projects including FleXtore II, Hydrous, and Cleantech Energy Crossing. Provides student research and technical expertise.
• AQUABATTERYcoreStrategic or Co-development PartnerDutch startup partner in SLDBatt consortium developing complementary battery technology (salinity gradients). Both companies part of new sustainable battery industry.
• Exergy StoragecoreStrategic or Co-development PartnerCompany partner in SLDBatt consortium specializing in energy storage technology development.
• NobiansupportingStrategic or Co-development PartnerNationally anchored industrial partner in SLDBatt consortium. Contributes to sustainable battery development with focus on circularity.
• RWEsupportingStrategic or Co-development PartnerInternationally operating energy company partner in SLDBatt consortium. Contributes to practical implementation of battery technologies.
• ShellsupportingTechnology or IntegrationResearch partner in Melody Project (EU-funded) investigating membrane-less flow battery concept. Collaboration with TU Delft, Fraunhofer ICT, and European universities.
• Fraunhofer ICTcoreTechnology or IntegrationEuropean research partner in Melody Project and battery ecosystem. Key expertise partner in integral European ecosystem development.
• Witteveen+BossupportingImplementation/ SI/ Consulting PartnerProject partner in FleXtore II project for scalable energy storage system development with external control and energy management.
• TNOsupportingTechnology or IntegrationResearch partner in FleXtore II project providing technical expertise for energy storage system development.

Scale indicators7 records

Recent moves8 records

Expansion highlights7 records

Broad incumbents

• Sumitomo Electric: Sumitomo Electric is a long-standing developer of vanadium redox flow battery systems for industrial and utility customers, a broad incumbent in flow battery storage targeting the same large-MWh applications as Elestor.
• BYD Energy Storage: BYD is a global battery and energy storage incumbent at utility scale, leveraging vertically integrated cell production to compete on price and supply assurance in the same stationary storage market as Elestor.
• Fluence Energy: Fluence is a broad incumbent integrating lithium-ion and other storage technologies for utility-scale projects globally, competing with Elestor on grid storage deployments while serving overlapping utilities and IPP customers.
• Tesla Energy (Megapack): Tesla's Megapack and energy business is a broad incumbent in utility-scale lithium-ion battery storage, with deep customer relationships among utilities and grid operators that Elestor must displace for long-duration projects.

Direct peers

• ESS Inc. ESS Inc. manufactures iron flow batteries for long-duration grid storage—the closest chemistry peer to Elestor's hydrogen-iron flow battery, targeting similar utility and commercial customers with independently scalable MWh capacity.
• Invinity Energy Systems: Invinity produces vanadium redox flow batteries for commercial and utility-scale long-duration storage, sharing Elestor's flow battery architecture with decoupled power/energy and targeting similar renewables-integration use cases.
• CellCube (Enerox): CellCube (formerly Enerox/Gildemeister) manufactures vanadium redox flow battery systems for grid and commercial storage, a direct flow battery peer with independent power/energy scaling and similar utility customers.

Emerging players

• Highview Power: Highview Power develops liquid air / cryogenic long-duration energy storage for utility-scale applications—an adjacent technology targeting the same long-duration, large-MWh storage window that Elestor addresses.
• Form Energy: Form Energy is developing iron-air battery systems aimed at 100+ hour grid storage—an emerging LDES technology using abundant iron chemistry, directly competing with Elestor for the same bridging-Dunkelflautes opportunity.
• Energy Vault: Energy Vault develops gravity- and kinetic-based long-duration storage solutions, an emerging player addressing the same utility-scale 8–100+ hour storage use case via a non-electrochemical approach.

Market position

Strengths5 records

Weaknesses5 records

Competitive moat5 records

Key risks6 records

Key highlights7 records

Customer concentration

• LinkedInlinkedin.com/company/elestor

Revenue estimate

Valuation estimate

Number of profiles

Profiles7 records

Funding overview

Funding rounds1 record

Investors6 records

Funding detail is available on the Subscription and Enterprise plan.Contact sales →

M&A

Investments

M&A and investment is available on the Subscription and Enterprise plan.Contact sales →

Frequently asked questions about Elestor