Proof-of-concept of HT electrolysers at a scale > 70 kW

Topic description

Specific Challenge:

HT electrolysis has great advantages in terms of thermodynamics and transport phenomena, good possibilities of thermal optimization (through system integration), and so high potential of high value efficiency. Necessarily it has to demonstrate its potential.

HT electrolysis allows reaching much higher efficiencies compared to water electrolysis, which makes this process of prime interest for hydrogen production for different applications (hydrogen production for transportation or other direct industrial usages and renewable energies integration and storage). In this case, materials selection and/or development is necessary.

Considering economic factors, some studies exist with CAPEX and OPEX analysis, leading to a levelized cost of hydrogen for the size of installation considered^[1]. For units producing 100 kg of H2 per day, the CAPEX of HT electrolysis is close to the one of PEM water electrolysis, but higher than for alkaline electrolysis. However, thanks to its better efficiency, the levelized cost of hydrogen is below the one of PEM electrolysis whatever the price of electricity, and that it becomes competitive with alkaline electrolysis for an electricity price above 100 €/MWh. These elements highlight the potential of this technology compared to the other electrolysis technologies, and give lots of sense for demonstration project to demonstrate this expected benefit in real environment.

High performances have been validated over the last years (former Relhy and Adel projects) and major improvements have been achieved in terms of durability at stack level, both contributing to an increase of the maturity of the technology. Only few tests have been performed at the system level.

Therefore, there is a strong interest to prove the potential of this technology at the system level and at a scale above 70 kW. A single module or a sum of several modules can realize the target higher power range, to support different market applications with the same technology.

Proposals should address:

• The design and construction of a HT electrolyser including all balance of plant components for thermal, gas and electrical management, with:
  • Minimum capacity of 70 kW
  • Overall electrical efficiency on or above 68% based on higher heating value
  • Lifetime of at least 2,000 hours.
• In-field tests of the HT electrolyser system in a relevant environment for at least 6 months
• Assessment of the techno-economic performance of HT electrolysis in comparison to other water electrolysis technologies

The proposal is expected to have the following impacts:

• Contribution to achieve a target efficiency as indicated in the “Electrolysis Study” from FCH-JU, decreasing electricity consumption to below 40 kWh/kg H2
• In-field tests of HT electrolysis under representative conditions and scale as reported in the scope section and validation of the target performances
• Identification of business cases where HT electrolysis is more cost competitive than PEM and alkaline electrolysis

[1]M. Reytier, S. Di Iorio, A. Chatroux, M. Petitjean, J. Cren, J. Mougin, “Stack Performances in High Temperature Steam Electrolysis and Co-Electrolysis”, WHEC2014, June 15th-20th 2014, Gwangju, Korea (2014)”