Periodic Reporting for period 1 - PEACE (Pressurized Efficient Alkaline EleCtrolysEr (PEACE))
Berichtszeitraum: 2023-06-01 bis 2024-11-30
The reduction of emissions of carbon dioxide (CO2) required to achieve the goal of a climate-neutral continent by 2050, represents a significant challenge within the EU Green Deal. The EU hydrogen roadmap states directly that green hydrogen (powered by renewable sources) is crucial for deep decarbonization. Alkaline water electrolysis (AEL), among all electrolysers, provides highest technology readiness, lowest investment and maintenance costs and longest service time without using noble metals. The reduction of the levelized cost of hydrogen (LCOH), needed in order to boost the competitiveness of green H2, can be achieved by enhancing the operating efficiency at higher current densities, as well as by enabling better integration with downstream processes. Moreover, the adaptation to fluctuating power supply should be enhanced for direct coupling with renewables. In addition, the operation of AEL systems at pressures of significantly more than 30 bar makes it possible to dispense with further stages of mechanical compression, so that the high-pressure hydrogen generated can be fed directly into gas networks or used directly for chemical processes such as methanol synthesis. Highly pressurized AEL with modified stack and balance of plant (BOP) design and innovative pressurization concept is proposed in the research and innovation project ‘Pressurized Efficient Alkaline Electrolyser’ (PEACE) that has the potential to exceed the planned FCH2 JU’s KPI targets in terms of cost, efficiency, lifetime and operability by the year 2025.
A new concept of hydrogen production with two-stage pressurization is being developed and demonstrated on an AEL system of more than 50 kW capable of operating at pressures exceeding 50 bar. The integration of advanced components, innovative design, and optimized operation strategies is being explored through modelling and experimental testing, ultimately aiming to demonstrate a system with impressive efficiency characteristics.
PEACE places a strong emphasis on sustainability and circularity aspects – a Life Cycle Assessment of the PEACE technology is being conducted to quantify its environmental impacts.
A new concept of hydrogen production with two-stage pressurization is being developed and demonstrated on an AEL system of more than 50 kW capable of operating at pressures exceeding 50 bar. The integration of advanced components, innovative design, and optimized operation strategies is being explored through modelling and experimental testing, ultimately aiming to demonstrate a system with impressive efficiency characteristics.
PEACE places a strong emphasis on sustainability and circularity aspects – a Life Cycle Assessment of the PEACE technology is being conducted to quantify its environmental impacts.
The project scientific tasks are summarized in the following paragraphs.
WP2: Cell components development and qualification
Cell component qualification has been carried out by different partners in the project, consisting of both electrochemical and gas purity tests. Electrochemical results show that the best performance is highly dependent on the substrate of choice, which are modified with Raney nickel. The performance further improved once the conventional separator was replaced by alkaline membrane. Experiments with a small gap between the cathode and the separator show that crossover can be reduced, but a too large gap can lead to a significant increase in ohmic resistance. Based on the obtained results recommendations have been made for the larger scale tests.
WP3: Stack development for highly pressurized AEL
Materials were selected and mechanically validated, while the gantry mill machine for the realization of the prototypes was purchased. The bipolar plates and the end plates design are completed and ready to be produced. On the elastic elements, tests were performed to grant an optimal electrical contact between the bipolar plate and the electrode itself. Spot welding techniques for the contacts are tested and validated, while the choice between flat gaskets and o-ring is left to the first full scale physical realization. Fluorinated plastics are now completely excluded from the design, improving sustainability.
WP4: Proof of concept, adaptation, operation and validation
P&ID for the modifications required to extend current setup for a dual-stage pressure AEL system has been drafted and finalized. The old stack has been successfully disassembled, and preparations are in place to mount the new stack once it is developed. Further discussions with MMI will ensure that the integration and mounting of the new stack onto the pressure vessel are seamless and problem-free. Suitable hardware suppliers have been identified, enabling quotations from installation companies to align with the allocated budget. A first HAZOP frame is now ready from MMI. Being HAZOP an iterative process, this phase will last for all the time PEACE project will be active.
WP5: Operation strategies and simulations
One of the goals of the project is to optimize the system operation based on numerical simulations. As starting point, 2 simulation scenarios (ammonia or methanol production with an upstream integration to a combination of wind and solar power) has been stablished. For each scenario the output capacity, feedstock requirement, electrical power consumption, minimum operative capacity, pressure range, and times required for ramp-up and down were defined. Regarding the electrolyzer modelling, the existing TEMPEST framework was being extended to enable the modelling of rectangular electrolysis cells. Three cells were interconnected to form a simplified stack model. The gas-liquid separator, pressure bell, electrolysis cell and stack were parameterised with parameters from the BTU test stand and with the data defined from the stack development in WP3.
WP6: Circularity, dissemination, exploitation and communication
A literature review of LCAs on state-of-the-art technologies for AEL systems was carried out to establish a reference technology. The outcome of the literature review is that we need to model the reference technology in all details by ourselves in order to offer a fair and stringent comparison; the literature review revealed large differences in climate change impacts apparently depending on choices of functional unit, boundaries, energy supply and different degrees of including the BOP and the end-of-life of the plant. Current European guidelines on doing LCA on H2-producting technologies have being consulted; including a comparative study by the JRC. It was decided to cut the comparison before the synthesis into methanol and/or ammonia, since the last part would be identical for the PEACE technology and for the reference technology. This would also allow for a potential delivery of the LCA results as a product environmental foot print for H2.
WP2: Cell components development and qualification
Cell component qualification has been carried out by different partners in the project, consisting of both electrochemical and gas purity tests. Electrochemical results show that the best performance is highly dependent on the substrate of choice, which are modified with Raney nickel. The performance further improved once the conventional separator was replaced by alkaline membrane. Experiments with a small gap between the cathode and the separator show that crossover can be reduced, but a too large gap can lead to a significant increase in ohmic resistance. Based on the obtained results recommendations have been made for the larger scale tests.
WP3: Stack development for highly pressurized AEL
Materials were selected and mechanically validated, while the gantry mill machine for the realization of the prototypes was purchased. The bipolar plates and the end plates design are completed and ready to be produced. On the elastic elements, tests were performed to grant an optimal electrical contact between the bipolar plate and the electrode itself. Spot welding techniques for the contacts are tested and validated, while the choice between flat gaskets and o-ring is left to the first full scale physical realization. Fluorinated plastics are now completely excluded from the design, improving sustainability.
WP4: Proof of concept, adaptation, operation and validation
P&ID for the modifications required to extend current setup for a dual-stage pressure AEL system has been drafted and finalized. The old stack has been successfully disassembled, and preparations are in place to mount the new stack once it is developed. Further discussions with MMI will ensure that the integration and mounting of the new stack onto the pressure vessel are seamless and problem-free. Suitable hardware suppliers have been identified, enabling quotations from installation companies to align with the allocated budget. A first HAZOP frame is now ready from MMI. Being HAZOP an iterative process, this phase will last for all the time PEACE project will be active.
WP5: Operation strategies and simulations
One of the goals of the project is to optimize the system operation based on numerical simulations. As starting point, 2 simulation scenarios (ammonia or methanol production with an upstream integration to a combination of wind and solar power) has been stablished. For each scenario the output capacity, feedstock requirement, electrical power consumption, minimum operative capacity, pressure range, and times required for ramp-up and down were defined. Regarding the electrolyzer modelling, the existing TEMPEST framework was being extended to enable the modelling of rectangular electrolysis cells. Three cells were interconnected to form a simplified stack model. The gas-liquid separator, pressure bell, electrolysis cell and stack were parameterised with parameters from the BTU test stand and with the data defined from the stack development in WP3.
WP6: Circularity, dissemination, exploitation and communication
A literature review of LCAs on state-of-the-art technologies for AEL systems was carried out to establish a reference technology. The outcome of the literature review is that we need to model the reference technology in all details by ourselves in order to offer a fair and stringent comparison; the literature review revealed large differences in climate change impacts apparently depending on choices of functional unit, boundaries, energy supply and different degrees of including the BOP and the end-of-life of the plant. Current European guidelines on doing LCA on H2-producting technologies have being consulted; including a comparative study by the JRC. It was decided to cut the comparison before the synthesis into methanol and/or ammonia, since the last part would be identical for the PEACE technology and for the reference technology. This would also allow for a potential delivery of the LCA results as a product environmental foot print for H2.
The first results from the cell components qualifications show at least 1 Acm-2 at a cell potential of 1.8-1.95V in combination with good gas purities over an operation range of 10-100%. These results are aligned with the main expected results from PEACE, which are the development and demonstration of an AEL system > 50 kW capable of operating up to 90 bar, with an efficiency of 70 % (LHV) at a current density of 1 A/cm2 in high KOH concentration feedstock at 80 °C. Furthermore, the cost reduction is expected by replacing fluorinated plastic as a stack material for cheaper plastics enabling of withstand high pressures.