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Conclusion: Under the most demanding combination of operating conditions, which involves partial load and pressurized operation, a shunt circuit design must be adopted, along with the implementation of efficient strategies for liquid level and concentration balance to maintain impurity concentrations within safe limits. Research indicates that the adaptability of a shared electrolyte circulation to this combination of operating conditions is highly sensitive and unstable.

IV. Power Outage and Low Voltage Management

Under the premise of maintaining impurity concentrations within safe limits, the system can briefly tolerate operation below the lower load limit, but electrode voltages must be strictly controlled:

Cathodic protection voltage: When the cathode voltage drops below approximately 0.25 V, the deterioration (such as corrosion and dissolution) of the electrode material significantly accelerates.

Safety redundancy: Even if impurity concentrations are controllable, once the voltage approaches this threshold, immediate shutdown is required to protect the electrodes.

Countermeasures:

Capacitive effect buffering: Modern multi-layer composite electrode structures can exhibit a certain capacitive effect (equivalent to a large internal capacitor). Experiments have demonstrated that after a complete power outage, this effect can slow down the rate of electrode voltage drop, providing time for the system to restart. Research data indicates that if power can be restored within 10 minutes after a power outage, it may be possible to avoid shutdown and maintain continuous operation, significantly enhancing the system's ability to cope with transient fluctuations.

V. Complexity of Temperature Management

Partial load operation also poses significant challenges to system temperature control:

Narrow optimal efficiency range: Alkaline electrolysis typically achieves optimal efficiency between 50-80°C (with high conductivity and no significant material deterioration).

Insufficient heat at reduced loads: As the load decreases, the reaction heat (ohmic heat and reaction enthalpy) also decreases. In low ambient temperatures or with insufficient insulation, the system struggles to maintain temperatures above the minimum of 50°C (which compromises efficiency and safety).

High load and high temperature require heat dissipation: Under full load or high ambient temperatures, an effective cooling system is required to prevent temperatures from exceeding the upper limit (typically 80-90°C) to avoid accelerating material degradation or exacerbating corrosion.

VI. External Strategies for Coping with Partial Load Fluctuations

To effectively cope with power fluctuations below the lower load limit (such as 10%-25%) and avoid frequent startups and shutdowns, external strategies are often required to keep the electrolyzer submodules operating at higher loads:

Power fluctuation buffering: Integrate energy storage systems (such as batteries, supercapacitors, or flywheels) to smooth out rapid fluctuations in renewable energy and provide a stable DC input.

Electrolyzer stack grouping operation: Divide large electrolysis systems into multiple independent submodules. When the total demand power decreases, some sub-modules can be shut down (put into shutdown or standby mode), while maintaining the operation of the remaining sub-modules close to their rated loads.

Technical challenges:

Load distribution algorithm: efficiently and flexibly distributing power fluctuations to different sub-modules.

Thermal state management: managing the temperature rise, fall, and insulation requirements when starting and stopping different sub-modules.

Operational history recording and analysis: accurately tracking and recording the start-up times, operating durations, and load curves of each sub-module for evaluating aging status, predicting lifespan, formulating precise maintenance plans (such as electrode replacement), and optimizing operational strategies.