Logo GrInHy


Clean Hydrogen from renewable energies is key to a successful cross-sectoral energy transition enabling the EU’s low-carbon economy goal in 2050. However, access to renewable electricity will be a limiting factor in the future and energy efficient technologies will still be important. Due to a significant energy input in form of steam preferably from industrial waste heat, High-Temperature Electrolysis based on Solid Oxide Electrolysis Cells (SOEC) achieves outstanding electrical efficiencies.


Project Overview

Essential element of the GrInHy2.0 project is to produce hydrogen the most energy efficient way while increasing the technological maturity of the High-Temperature Electrolyser (HTE). Although starting with hydrogen production for today’s steel annealing processes, GrInHy2.0 marks an important milestone towards a hydrogen-based, low carbon European steel industry. Here, hydrogen has the potential to reduce today’s process related CO2 emissions by more than 95 %.

The Salzgitter companies Salzgitter Flachstahl GmbH and Salzgitter Mannesmann Forschung GmbH together with the partners Sunfire GmbH, Paul Wurth S.A. Tenova SpA and the French research centre CEA will work together at the world’s most powerful HTE for the energy efficient production of hydrogen. Further, the consortium will contribute to a detailed analysis of the potentials of renewable hydrogen in the iron-and-steel industry as well as the in-depth understanding of SOEC long-term behaviour on stack level.

With the first implementation of a high-temperature electrolyser of the Megawatt-class, GrInHy2.0’s prototype will produce 200 Nm³/h of hydrogen at nominal power

input of 720 kWAC. The HTE system consists of up to eight modules with 720 or 1,080 SOECs each, i.e. 24 or 36 stacks, respectively.

As in the predecessor project GrInHy, the prototype will be fully integrated into Salzgitter’s steelmaking operations and will run on steam from waste heat of the steel production. By the end of 2022 it is expected to have been in operation for at least 13,000 hours, producing a total of around 100 tons of high-purity ‘green’ hydrogen at electrical efficiency of minimum 84 %LHV.

In parallel to the prototype testing operation, a singular stack of the SOEC technology will set new standards in long-term testing with a test bench operation of at least 20,000 hours. The test will not only show the technology’s increased robustness but also provide potential starting points for further improvement.

In a broader perspective, the project will also deliver answers on how to avoid CO2 emissions in the European steel industry by switching to a hydrogen-based primary steelmaking and what it takes.

Technical Objectives


Electrolyser scale-up to 720 kWel,AC producing 200 Nm³/h (18 kg/h)


Electrical electrolyser efficiency up to 84 %el,LHV (< 40 kWhel,AC/kg)

13,000 operating hours

< 13,000 operating hours at system level with a proved availability of < 95 %

20,000 operating
hours at
stack level

< 20,000 operating hours at stack level

hot start

Demonstrate hot start from minimum to maximum power in < 5 mins

>100 tons of
green hydrogen

Produce >100 tons of green hydrogen at under 7 €/kgH2


Reduce electrolyser CAPEX to <4,500 €/(kgH2/d)


Provide techno-economic studies for further market deployment



Create viable technology

Create viable technology by demonstration in a complex industrial environment

Assess CO2

Assess CO2 avoidance potential of a hydrogen-based European steel industry

green hydrogen

Provide significant share of green hydrogen to the iron-and-steel works

purchasing on

Evaluate situation on purchasing renewable electricity and green H2 certification

Consortium Partner

Salzgitter Mannesmann Forschung GmbH (SZMF), centralized research and development (R&D) company of the Salzgitter Group, is responsible for the overall project coordination and the full Life Cycle Assessment of the Steam Electrolyser.

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Salzgitter Flachstahl GmbH (SZFG), site owner and operator of the iron-and-steel works, prepares the installation site, integrates the StE system into the existing infrastructure and is responsible for the operation and production of “green hydrogen”.

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Sunfire GmbH (SF), the developer and provider of the steam electrolyser from their European manufacturing including installation, operation and maintenance.

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Paul Wurth S.A. (PW), developer and provider of gas processing technologies will be responsible for the design and development of the HPU, which ensures the required hydrogen quality in terms of pressure and moisture. Additionally, PW will perform cost analysis to optimize service and maintenance strategy in order to achieve lowest life cycle cost. PW will further investigate routes for N2 cleaning for applications with higher H2 purity demands (5.0 qualities) or in case that the hydrogen quality of the electrolyser is not sufficient.

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Commissariat à l’énergie atomique et aux énergies alternatives (CEA), as a key player in research, development and innovation will provide long term stack tests as well as energy management strategy assessment as a support to StE design and on-site operation, and techno-economic analysis as a basis for further market development.

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Tenova (TENOVA), a developer of innovative technologies and services for the metal and mining industries will create a study on the CO2 avoidance potential of hydrogen in the European steel industry. With its ENERGIRON-ZR process, a direct reduction process (DR) able to use alternative reducing gases such as hydrogen on a large scale, represents the leading edge of gas-based reduction technologies and an ideal step into the upcoming hydrogen era.

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This project has received funding from the Fuel Cells and Hydrogen 2 Joint Undertaking (now Clean Hydrogen Partnership) under Grant Agreement No 826350. This Joint Undertaking receives support from the European Union’s Horizon 2020 Research and Innovation programme, Hydrogen Europe and Hydrogen Europe Research.



GrInHy2.0 - GREEN INDUSTRIAL HYDROGEN, Project Flyer, 19 April 2021


SZMF, GrInHy2.0 Project Progress Presentation, FCH2 JU Programme Review Days @ European Hydrogen Week 2021, 02 December 2021


Sunfire, Sunfire - Renewables Everywhere, AIST European Steel Forum 2021, CO2-Free Energy: The Evolution of Green Hydrogen, 27 October 2021


SZMF, Green Industrial Hydrogen for future green steelmaking, FCH2 JU Pre-Session @ EUSEW 2021, 18 October 2021


FCH2 JU, The Status of SOEC R&D in the European Fuel Cell and Hydrogen Joint Undertaking Programme, Event 'FCH2 JU meets GrInHy2.0', 14 July 2021


SZMF/Sunfire, Project Progress Presentation, Event 'FCH2 JU meets GrInHy2.0', 14 July 2021


Tenova, GrInHy2.0 - Another step towards hydrogen based steelmaking, Webinar Hydrogen Steelmaking, Steel Times International, 20 November 2020


SZMF, GrInHy2.0 and future hydrogen-based steelmaking, Virtual Site Visit @ Virtual Study Tour H2: Knowing Practical Hydrogen Applications, German-Chilean Chamber of Commerce and Industry, 02 October 2020


SZMF, Energy-efficient hydrogen production for today’s and future steelmaking, Virtual Forum about Hydrogen @ Mining: Best Practice Examples of Hydrogen Applications in Germany, German-Chilean Chamber of Commerce and Industry, 18 August 2020


FCH JU Success Story 2020, Gathering Steam: Green Hydrogen for Energy-Intensive Industries

Work Package 1 - Coordination & Management

D1.1 Management Guidelines

Work Package 3 - Technology Validation & Demonstration

D3.1 Definition of long term stack test protocol

Work Package 4 - Regulatory Framework

D4.1 Plan of action for the operational renewable electricity supply


D4.2 Assessment of hydrogen certification standards and requirements

Work Package 5 - Market, Techno-economic / Environmental Studies

D5.4 Hydrogen use in Direct Reduction (DR) Plant – potentials for CO2 mitigation in steel works

Work Package 6 - Dissemination and Exploitation

D6.1 Draft Communication and Dissemination Plan

Press Releases

Salzgitter AG & Sunfire GmbH, World’s Largest High-Temperature Electrolyzer Achieves Record Efficiency, Press Release, April 19th 2022


Salzgitter AG & Sunfire GmbH, EU Funding Body Visits the World’s Largest High-Temperature Electrolyser of Salzgitter Flachstahl GmbH, Press Release, July 14th 2021


Salzgitter AG, World’s largest high-temperature facility commences trial operation in Salzgitter, Press Release, December 10th 2020

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Salzgitter AG & Sunfire GmbH, GrInHy2.0: Sunfire delivers the world’s largest High-Temperature Electrolyzer to Salzgitter Flachstahl, Press Release, August 25th 2020


Salzgitter AG & Sunfire GmbH, GrInHy2.0 – Hydrogen for low-CO2 steelmaking, Press Release, March 14th 2019



This project has received funding from the Fuel Cells and Hydrogen 2 Joint Undertaking under grant agreement No. 700300. This Joint Undertaking receives support from the European Union’s Horizon 2020 research and innovation programme and Hydrogen Europe and N.ERGHY.

Green Industrial Hydrogen

As a proof-of-concept, the GrInHy project includes designing, manufacturing and operation of a reversible generator based on the Solid Oxide Cell technology in a relevant industrial environment. The project has been granted funding under the call FCH-02.4-2015 and was active from 03/2016 - 02/2019.

High-temperature electrolysis (HTE) is one of the most promising technologies to address the European Commission´s roadmap towards a competitive low-carbon economy in 2050. The decarbonization of Europe’s industry, transport and energy sector by higher shares of renewable energy sources (RES) requires a high flexibility in energy production, load management and large-scale storages. A reversible HTE providing green hydrogen or electricity to these sectors is a possible solution as a cross-sectoral technology. Since a significant share of energy input is provided as heat – preferably from waste heat, the HTE achieves outstanding electrical efficiencies resulting in an electricity demand of <40 kWh instead of 51-60 kWh per kg hydrogen in SoA low-temperature electrolysis.

Central element of GrInHy is the manufacturing, integration and operation of the worldwide most powerful reversible HTE prototype at an integrated iron-and-steel works. As a Research and Innovation Action, the project also focused on the improvement of robustness and durability of the HTE technology on cell and stack level.

The project’s main objectives were as follows:

  • Up-scaling of an HTE system (150 kWAC,EC) that can also be operated reversibly as fuel cell using either natural gas or hydrogen as fuels
  • Operation for at least 7,000 h meeting the hydrogen quality standards of the steel industry
  • Proof of reaching an overall electrical efficiency of at least 80 %LHV (ca. 95 %HHV) based on available steam from waste heat
  • Reaching a lifetime at stack level of greater than 10,000 h with a degradation rate below 1 %/1,000 h
  • Elaboration of a viable Exploitation Roadmap while showing the feasibility of future cost targets

Further Information

The Consortium

The consortium consisted of eight partners originated in five different EU countries including a technology specialized SME, large industries, university and non-university research organizations:

  1. Salzgitter Mannesmann Forschung GmbH
  2. Salzgitter Flachstahl GmbH
  3. Boeing Research and Technology Europe
  4. Sunfire GmbH
  5. VTT Technical Research Centre of Finland
  6. EIFER - European Institute for Energy Research
  7. Institute of Physics of Materials, Brno
  8. Politecnico di Torino

In total, more than 30 experts and researchers of different professions worked closely together to take the next steps of the HTE's Technology Readiness Level.

Work performed and main results achieved

Over the project duration of 36 months, all project’s objectives and milestones were reached with only minor deviations. A flexible and dynamically applicable prototype was successfully designed and manufactured with a nominal electrolyser capacity of 150 kWAC,EC (40 Nm³H2/h) and a maximal power of 200 kWAC,EC (50 Nm³/h). The prototype system was set-up in June 2017 and connected to a hydrogen processing unit in order to meet the integrated iron-and-steel-works requirements in terms of H2 purity and pressure. An efficiency of the HTE of 78 %LHV,EC (without drying and compression) was measured. This was related to the 88 % bi-directional power electronics efficiency, compared to 94% as specified, which would result in an HTE efficiency of 84 %LHV,EC.

Additionally, the fuel cell (FC) operation showed the system’s fuel adaptability: Operated with natural gas in fuel cell mode, the system reached the nominal power of 25 kWAC,NG-FC and a maximum AC efficiency of 52 %LHV,NG-FC at 80 % load (20 kWAC,NG-FC). With hydrogen, the nominal power was 30 kWAC,H2-FC and a maximum AC efficiency 48 %LHV,H2-FC. The reversible HTE was tested for typical dynamic cycles derived from load management and grid balancing.

The prototype was operated for approximately 10,000 h in electrolysis, fuel cell or hot-standby mode. Several optimizations on hardware and software level were performed, both for the reversible HTE and the hydrogen processing unit. In total, about 90,000 Nm³ of hydrogen were produced during electrolysis operation of which more than 41,000 Nm³ with a quality of 3.8 at 10 bar(g) were used for annealing processes at Salzgitter’s integrated iron-and-steel works.

Cells and stacks were optimized and tested e.g. for degradation and mechanical properties on cell and stack level resulting in material improvements and optimized stack integration. Due to contaminations and failures of the test bench, the foreseen 10,000 h continued stack testing was aborted after 8,300 h. Another stack under optimized test conditions reached degradation rates well below the project target of <1 %/kh for more than 5,000 h. More than 80,000 ultra-fast load cycles (direct on/off-switching of current) on cell level and more than 16,000 cycles at stack level were performed without increased impact on the degradation rate.

The technology’s cost structure, potential business cases and environmental performance were assessed in accompanying studies. Based on all results, a comprehensive exploitation roadmap was elaborated laying the foundation for the HTE towards a marketable product.

GrInHy achieved a high-level of public awareness during scientific conferences, international fairs and dedicated hydrogen technology workshops. The project reached numerous political decision makers, researchers and possible costumers while exchanging results with other FCH2-JU projects. Due to its results, GrInHy was nominated for the FCH JU Awards 2018 “Best Project Innovation”.

Progress beyond the state of the art, expected results until the end of the project and potential impacts

The consortium has implemented a reversible HTE system that is world-wide leading in terms of scale, efficiency, operation and fuel flexibility and first-time integration in an industrial environment. As unique feature, the HTE system operation is able to switch from electrolyser to fuel cell mode using either natural gas or hydrogen as fuel. Even the potential usage of process gases from steel production processes was investigated and found to be suitable after additional reforming and cleaning steps.

The main impact of GrInHy are the proof-of-concept of the technology and its potentials in an industrial environment and the exploitation of the project’s results to improve the HTE's Technology Readiness Level. Most of the results will be directly realized in the successor project, GrInHy2.0, that already has been started in January 2019.

GrInHy’s prototype operation showed that an electrical AC efficiency of 84 %LHV,EC based on steam from waste heat is possible. This indicates approx. 25 % higher electrical efficiencies compared to low-temperature electrolysers. This power consumption of below 40 kWhAC per kg hydrogen will be verified in GrInHy2.0. Since electricity costs have a share of about 70-80 % of total costs in the long-term, HTE is a key technology to achieve economic feasibility for hydrogen production from RES.

GrInHy provided a comprehensive scale-up study of the HTE to reach the multi-MW class lowering the costs to less than 1,000 €/kWAC,EC within the next five years. In GrInHy2.0, the world wide first HTE of the MW class will be operated at the integrated iron-and-steel works in Salzgitter.

The operation of the next HTE prototype generation in Salzgitter will also intensify SZFG’s and SZMF’s efforts to investigate alternative steel production pathways that directly avoid CO2 emissions (Carbon Direct Avoidance). A very promising approach is Salzgitter’s SALCOS concept which is based on the substitution of carbon with hydrogen as a reducing agent resulting in CO2 reductions of up to 95 % or more than 150 million tons of CO2 per year in the EU 28. In this context, GrInHy and GrInHy2.0 are a technological preliminary study of an energy efficient hydrogen production providing green hydrogen for the steel industry in the future.


GrInHy's public deliverables are published at the Community Research and Development Information Service (CORDIS) of the European Commission.Seite aufrufen

EIFER, Long-term Fast Current/Power Cycling at Solid-Oxide Electrolyser Cells, WHEC 2018, 18 June 2018, Rio de Janeiro (Brasil)


SZFG, CO2-Reduktion in der Industrie: Grüner Wasserstoff im Hüttenwerk, 10. Niedersächsische Energietage, 08 November 2017, Hannover (Germany)


EIFER, Hydrogen Production with Steam Electrolysis: A Glance at 15 Years of Durability Research in EIFER, Celebration of EIFER's 15th Anniversary, 21 September 2017, Karlsruhe (Germany)


Sunfire, Green Industrial Hydrogen via Reversible High-Temperature Electrolysis, ECS Meetings – SOFC-XV: 15th International Symposium on Solid Oxide Fuel Cells, 23 - 28 July 2017, Hollywood - Florida (USA)


EIFER, Long-term Steam Electrolysis with Solid Oxide Cells with up to 23 000 h Operation, 7th World Hydrogen Technology Convention, 9 - 12 July 2017, Prague (Czech Republic)


Sunfire, Steam Electrolysis as the Core Technology for Sector Coupling in the Energy Transition, International Conference on Electrolysis, 12 - 14 June 2017, Copenhagen (Denmark)


SZMF, GrInHy – Grüner Wasserstoff in der Stahlherstellung, Efficient and emission free – establishment of hydrogen and fuel cell applications, 07 June 2017, Salzgitter (Germany)


SZMF, GrInHy Project, Wasserstoff- und Brennstoffzellentechnologie – Bundesförderung und Projekte in Niedersachsen, 20 February 2017, Hannover (Germany)


SZFG, GrInHy Project, German Power to Gas Strategy Platform, Workshop, 29 September 2016, Berlin (Germany)


POLITO, New Glass-Ceramic Sealants for SOEC Applications, 41st ICACC, 22 – 27 January 2017, Daytona Beach (USA)


IPM, Thermo-Mechanical Behaviour of Multi-Layered Ceramic Systems for SOFCs, 41st ICACC, 22 -27 January 2017, Daytona Beach (USA)


Sunfire, GrInHy Flyer, 2019