THE STORY OF IRON ENERGY

Born as an ETH spin-off, IRON ENERGY builds on Swiss excellence in innovation and engineering. We developed a long-duration energy storage solution feasible for seasonal storage — enabling communities and industries to achieve energy self-sufficiency. By combining sustainability with resilience, we are helping to transform today’s energy system into one that is ready for the future.

WE POWER IRON ENERGY

IRON ENERGY is powered by a team of four entrepreneurs who bring together diverse backgrounds and complementary strengths. From cutting-edge research in energy systems to hands-on experience in engineering, business strategy, and project execution, we combine the competencies needed to turn vision into reality. What unites us is a shared drive: to build solutions that make sustainable, self-sufficient energy a reality for communities and industries.

Innovative Technology

Swiss Quality

Integrable Solution

Durable Design

Meet the Team (left to right):

• Dr. Lauri Lehtonen – COO

• Brian Petrus – Head of Engineering & Projects

• Dr. Samuel Heiniger – CEO & CTO

• Daniel Bloch – CFO

27 %

of solar power is sold at negative prices

7.2 bilEUR

of electricity was curtailed in Europe in 2024

up to 900 hours

of electricity was sold at negative prices in Europe in 2024

Did you know?

Step 1: Conversion of Power

• Electrical energy is supplied to the reversible solid-oxide fuel cell / rSOFC.

• The rSOFC operates in the charing phase as an electrolyzer:

  • Steam is fed into the cell.

  • Hydrogen is produced while oxygen is released.

Step 2: Charging the Iron Battery

• The generated hydrogen is introduced into the storage vessel, which is filled with iron oxide (FeOx), under atmospheric pressure:

  • At around 500°C, the hydrogen reacts with the iron oxide, producing steam and metallic iron (Fe).

  • The resulting steam leaves the reactor and returns towards the rSOFC side.

Step 3: Energy Storage

• The iron now serves as a stable, solid energy carrier.

• The electrical energy is stored in the form of chemical energy within the metallic iron.

• This charged state allows for indefinite and safe storage, with the material ready to be triggered to release energy on demand for later use.

IRON ENERGY'S HIGH-TEMPERATUR

IRON-AIR BATTERY

Step 1: Hydrogen Release from the Iron Battery

• Steam is introduced into the reactor:

  • Metallic iron is oxidized and release hydrogen in an exothermic process

  • The storage material remains stable — the iron oxide stays inside the vessel and is reused for the next charging cycle.

  • The released hydrogen is directed to the rSOFC

Step 2: Power Generation in the rSOFC

• The rSOFC now operators as a fuel cell:

  • Hydrogen and air and is consumed

  • Electricity and steam (500°C) is generated

Step 3: Energy Output

• Electrial power is delivered to the load

• The remaining energy is released as high-temperature heat (500°C), which can be utilized for thermal applications.

Energy

Our storage systems achieve power-to-power efficiencies of up to 60%, while the remaining energy is available as high-temperature heat. It delivers an energy density of up to 2.8 MWh/m³—approximately 8× higher than lithium-ion batteries.

Advantages of Iron Energy

Sustainability

The process relies entirely on naturally abundant resources, and it is designed in a way that avoids the use of any harmful, hazardous, or toxic materials.

Safety

The system operates safely in a solid state at ambient pressure — eliminating the risk of explosion.

Costs

The usage of iron oxide allows to cut costs by 20 times cheaper than Li-ion batteries. Operative costs are marginal due to non-moving part design and non observable degradation of the material.

Integrability

The technology integrates effortlessly and harmoniously into the existing energy infrastructure.

Scalable

A well-established global market already exists for all components and materials involved, ensuring large-scale availability, reliable supply chains, and cost efficiency.

Where to integrate our systems

RENEWABLE ENERGY PROJECT

WASTE INCINERATION PLANT

WASTE WATER TREATMENT PLANT

CRITICAL INFRASTRUCTURE

RESERVE MARKET

We develop and build large-scale, stationairy long-duration energy storage systems - tailored to each customer's energy profile and requirements.

ENERGY COMMUNITIES

Let's talk storage solutions

Have a question about our technology, or interested in integrating a storage system for your energy needs?

Reach out today.

What we do

SEASONAL ENERGY STORAGE PILOT REACTOR

In 2023, our founder, Dr. S. Heiniger, commissioned a 10 MWh pilot plant at ETH Zurich's Hönggerberg campus as part of his PhD research at the Functional Materials Laboratory. The facility consists of three stainless-steel storage tanks and demonstrated the scalability of Iron Energy's seasonal energy storage technology beyond laboratory scale. The pilot plant operates as a fully integrated power-to-power storage system, using electricity and water. With a storage capacity of 10 MWh, it contains enough energy to cover the annual electricity demand of approximately three to five typical households.

CE-CERTIFIED DEMONSTRATOR (20 MWh / 200 kW)

To demonstrate the scalability and long-term reliability of our technology, Iron Energy is currently commissioning a 20 MWh, CE-certified demonstration plant with a hydrogen storage capacity of 650 kg. The facility will complete 50 full operating cycles in 1.5 years, providing critical performance data under industrial conditions. Successful operation of the demonstrator will elevate the technology from TRL 6 to TRL 8. The plant is scheduled to enter operation in late summer 2026 and is partially supported by an Innosuisse innovation grant.

The Gen2 prototype of the energy storage system with an internal volume of 210 liters was built on a small scale in the laboratory by the Functional Materials Laboratory (Prof. Dr. W. Stark) at ETH Zürich. This provided valuable insights into the process and design of the system, which will contribute to the optimization of future storage tanks.

• 250 kg iron ore

• Approximately 250 kWh of energy storage capacity

RESEARCH & DEVELOPMENT

Zurich, Switzerland

Grenzach-Wyhlen, Germany

Zurich, Switzerland

SWISS DATA CENTER ENERGY STORAGE PROJECT

The first commercial Iron Energy installation will be located in the basement of a major Swiss data center operator (NTS Workspace AG) as part of the expansion of its existing facility in Bern. The project will become the largest battery in Switzerland by energy capacity.

The Iron Energy battery will decarbonize the data center's backup power system while creating additional value streams through energy arbitrage, peak shaving, and participation in the reserve power market. Furthermore, excess heat generated during operation will be recovered and sold to local industry, maximizing overall system efficiency and supporting regional decarbonization efforts.

GREEN AND AUTARK BUILDING COMPLEX IN ZÜRICH

The redevelopment of the Urdorf, Zurich residential district includes more than 200 new apartments, a double kindergarten, and an innovative integrated energy concept. A 500 MWh Iron Energy seasonal storage system is planned to store excess solar electricity during summer and make it available in winter. The storage system can be safely installed underground and within the residential area and will be integrated with rooftop photovoltaics, geothermal probes, heat pumps, and free cooling. Waste heat generated during discharge will be used within the district, creating a highly efficient, low-carbon, and largely energy-autonomous community.

Customer: NTS Workspace AG

Size: 3'000 MWh / 6 MW

Project Phase: Basic Engineering

Location: Bern, Switzerland

Start: 2026

Commissioning: 2028 (planned)

Customer: GEWOBAG

Size: 500 MWh / tbd

Project Phase: Feasibility Study

Start: 2026

Commissioning: 2030 (planned)

LABORATORY-SCALE REACTOR (GEN2)

COMMERCIAL PROJECTS

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