Record efficiency for the largest high-temperature electrolyser in the world

New success of the green steel program of the German company Salzgitter: the green hydrogen plant has a nominal efficiency of 84%.

200 Nm3 of green hydrogen produced per hour for the first time.

The corporate strategy of the steel group Salzgitter has one main objective: to drastically reduce its carbon footprint by 2033.

One of the tools to achieve this is the project GrinHy2.0who provided the company the largest high temperature electrolyser in the world for the production of green hydrogen.

The initiative, in which Sunfire, Paul Wurth, Tenova and the French research center CEA are also participating, has several objectives. At the same time, it offers a detailed analysis of the potential of the medium in the steel industry and an in-depth understanding of the behavior of solid oxide electrolysis cells (SOEC). The results are not expected.


The largest and most efficient high temperature electrolyser in the world.

We have been working with our partners on this emblematic project for many months. We have now taken an important step.

For the first time, the electrolyser produced 200 Nm3 of green hydrogen per hour.

We can also demonstrate an electrical efficiency of 84% (PCI). This is a level of efficiency that no one has achieved before. In comparison, other electrolysis technologies, such as alkaline batteries or PEMs, only achieve efficiencies of around 60% (PCI).

Simon Kroop, project manager.

The system consists of eight modules with over 700 SOEC cells each. And it operates at temperatures of 850°C, using waste heat from Salzgitter’s steelmaking processes.

This is why our high-temperature electrolyser requires much less electricity to produce hydrogen on a large scale than conventional technologies. As part of GrinHy2.0, we were finally able to demonstrate high efficiency at the megawatt scale.

Konstantin Schwarze, Sunfire Product Development Manager.

The prototype integrated into Salzgitter operations is expected to reach at least 13,000 hours by the end of 2022, producing a total of approximately 100 tonnes of high purity green hydrogen.

Along with testing the world’s largest electrolyser, the consortium will focus on a single stack of SOEC technology to set new standards for long-term testing with at least 20,000 hours of bench operation.

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