Research > Program No. 1: Technological Experimental Circuits > RA9 Hydrogen Technologies

RA9 Hydrogen Technologies


Within in research program “Technological Experimental Loops” one task is to build up an experimental facility for hydrogen generation by high-temperature water electrolysis using high-temperature helium and heat recovery. I.e. to study hydrogen production using heat from nuclear reactor.

Scientific approach

The testing of high-temperature electrolysis using heat from another technological process should show if this coupling is technically possible, economically reasonable, and should clarify the long-term degradation behavior of the incorporated components and materials. Therefore a loop was planned, where the central component is a heat exchanger for gas and water steam. Figure 1 is a schematic sketch of the planned system. The gas side of the heat exchanger simulates a high-temperature process, in the beginning a high-temperature gas reactor. The water side of the heat exchanger will supply the electrolysis system. The water supply allows for at least 1kW electrolysis stack. The first studies will be conducted with a ceramic dummy, later on it will be replaced by a commercial available stack.

Heat recuperation is implemented as well from the cathode as from the anode side gas stream. The aim is to create a system as energetic efficient as possible. Variations of the system in certain limits regarding temperature, pressure, and different types of gases are possible to simulate other high-temperature processes, e.g. bio mass gasification, new gas turbine processes, etc.

Figure 1: Scheme of hydrogen generation loop

In a second step of building up test facilities for high-temperature electrolysis, cell manufacturing and characterization will be implemented. This is necessary to get a deep insight in the cell behavior and to realize and test suggestions for improvement at cell and system level. Manufacturing will be concentrated on state-of-the-art oxygen ion-conducting, planar, ceramic cells with an edge-length of maximum 20cm. For the future, proton-conducted cells are not excluded from investigation as they enable a hydrogen production free from residue water.

As an outlook to future research of high-temperature electrolysis there are two more technologies, which have to be kept in mind. This is co-electrolysis of water and carbon dioxide and the reversible testing of ceramic cells in electrolysis and fuel cell mode.

For an economic application of the high-temperature ceramic cell all the named fields need to be investigated also in co-generation mode to verify the potential of this interesting and highly efficient technology.

Planned Experiments

Hydrogen production using co-generation
The testing of the hydrogen production via co-generation, see fig. 1, will initially concentrate on thermodynamics of the system, i.e. stationary and dynamical behavior. The most important parameters are therefore temperature and mass flow of the gas from the co-generation process and of the water steam for the electrolysis system.

1 Dynamic testing
The aim is to know, understand, and then be able to predict the characteristics of the system during heating- up and cooling down. This is necessary to estimate the needed time for starting the system and to avoid technical problems, mainly condensation of water, in the real application of such a system. The duration of tests will be in the range of some hours or days until the system has reached a stable state.

2 Long-term testing
For the prediction of operation characteristics, efficiency, and degradation behavior tests with duration of minimum 240h are planned.

Cell characterization
As mentioned above a further development of testing facilities is planned to produce and test ceramic cells. The produced cells will undergo two different types of testing: characterization and long-term testing.

1 Characterization tests
The electrochemical characterization of the cells will include all state-of-the-art methods, i.e. determination of gas-tightness of the electrolyte, measuring of U-i-curves, conduction of impedance analysis and gas analysis as well as post mortem studies of the tested cells to identify deposition or reaction of the cell materials.

2 Long-term tests
Long-term tests will be in the range of approx. 1000h. It is not enough to conduct long-term tests within the co-generation set-up. After the conduction of long-term tests with single cells it should be possible to separate the influence of the co-generation set-up and of the cell itself on the degradation behavior from each other. This approach enables a better interpretation of the degradation results.


As described in the previous chapters it is the aim of the Research Center Rez ‘CVR’ to establish a high-level research in the field of high-temperature electrolysis. The research started with the project SUSEN and the building-up of testing facilities. A first focus lays on hydrogen production via co-generation with a high-temperature gas-cooled nuclear reactor. Research activities should continuously grow and will include in future testing of ceramic cells in fuel cell as well as in reversible mode, and the manufacturing of planar cell.