The first reporting period mostly covered initial and preparational work: Sunfire manufactured the High-Temperature Electrolyser with a target capacity of 720 kWAC producing of 200 Nm³/h and Paul Wurth assembled the Hydrogen Processing Unit consisting of compressor and dryer. In the meantime, SZFG prepared the installation site. For the parallel stack testing, CEA installed and commissioned the test bench for the 20,000- hours testing period.
The second reporting period was mainly dedicated to the commissioning and operation of the GrInHy2.0 system prototype, on one hand, and long-term stack testing, on the other. The first hydrogen was injected during the commissioning stage in December 2020. As of December 2021, the prototype system reached 5,600 hours of operation and produced 42 t of ‘green’ hydrogen. This equalled a time availability of ~ 80 %. System downtimes were mostly due to hardware and software optimisations and installations of replacement HTE modules. Over the year 2021, the production capacity increased to a production rate of 170 Nm³/h with an HTE electrical efficiency of >84 %LHV.
Within the remaining 12 months almost all remaining operational targets were reached. In April 2022 the full capacity of 200 Nm³/h was successfully demonstrated and a record-high electrical efficiency of 84.6 %el,LHV could be communicated over all channels. By the end of 2022 the system was operating for more than 14,000 hours, injecting more than 100 tons of climate neutral hydrogen into the grid.
Dynamic testing showed that once the system is running, load change can be achieved quite quickly. A transient from 30 % load to full production takes less than 15 minutes. Main time-consuming action is the start of further HTE modules from Hot Standby to load operation. Furthermore, a normal shutdown of the system takes 3 minutes only. The long-term testing on the dedicated single-stack test bench experienced unforeseen challenges which is why the milestone of 20,000 h of operation on a single stack could not be achieved. Nevertheless, the dedicated test bench has been operated for a cumulated 17,000 h.
Our analysis of the CO2 avoidance potential of hydrogen for the European steel industry showed that the CO2 emissions of the entire European iron-and-steel industry can be reduced by more than 90 %. However, CAPEX requirements for carbon-neutral steel production are high and operation is only sustainable and economically viable if cheap green energy is available. Two techno-economic studies and one life cycle assessment add to our discussion of the HTE technology.
All project results are published via the European website as well as the project website and were additionally presented to an international audience at a conference in Salzgitter.
