グリーン水素のコスト平準化は、安価で間欠的な再エネ電力に耐える電解装置の設計によってのみ達成される

Unofficial AI-generated summary based on the public title and abstract. Not an official translation.

🔬研究者:電解装置の間欠運転劣化メカニズムとDWEの性能データを、水素コスト平準化研究の実証的基礎として活用できる。

🏢実務担当者:再エネ直接接続型水素プロジェクトの電解装置選定や耐久性・運転条件のリスク評価に役立つ。

🏛政策担当者:水素支援策や再エネ大量導入政策において、電解装置の部分負荷・サイクリング耐久性を評価軸に加える必要性を示す。

This paper examines why falling renewable electricity costs have not yet translated into cost-parity green hydrogen. It defines the technical requirements for electrolyzers operating directly on low-cost, intermittent solar and wind power and evaluates how conventional alkaline water electrolysis (AWE) and proton exchange membrane (PEM) systems perform under variable-load and repeated on/off cycling conditions. The paper combines techno-economic framing, literature-based engineering analysis, and novel decoupled water electrolysis (DWE) performance data. It reviews the role of electricity in the levelized cost of hydrogen and evaluates published evidence on alkaline and PEM behavior under partial load, dynamic input, shutdown, restart, and idle conditions. Key degradation and performance mechanisms assessed include shunt currents, gas crossover, reverse-current corrosion, catalyst dissolution, membrane thinning, and transient gas-composition instability. The analysis shows that access to cheap renewable electricity is necessary but insufficient for low-cost green hydrogen production. The lowest-cost electricity is typically intermittent, behind the meter, curtailed, or directly linked to renewable generation. Conventional electrolyzers were designed for stable baseload electricity. Due to inherent engineering limitations, they struggle under intermittency. Under variable load, AWE suffers from shunt current losses and gas crossover, severely reducing efficiency and limiting safe operation at low loads. PEM can follow load but incurs accelerated catalyst degradation (Ir/Pt dissolution) and membrane degradation (ROS-driven thinning), shortening system lifetime. Under repeated ON/OFF cycling, AWE experiences reverse-current-driven electrode corrosion and phase degradation, rapidly degrading performance. PEM suffers from small gas crossover during idle periods; unlike during normal operation, these gases are not swept away and can accumulate during shutdown, accelerating corrosion of both the electrocatalysts and the membrane. These findings are compared with performance data from a membraneless DWE architecture that temporally separates hydrogen and oxygen evolution. The reported results show specific energy consumption near 50 kWh/kg H2 over more than 10,000 cycles, normalized electrode performance through more than 50,000 accelerated cycles, and set-level current efficiency above 95% at 10% load and approaching 99% at higher loads. Calculated set specific energy consumption remained approximately 47 to 51 kWh/kg H2 from 10 to 100% load. These development-scale results support the architecture's ability to operate efficiently under variable power but do not establish field lifetime or project-level cost parity. The paper concludes that competitive renewable hydrogen requires electrolyzer architectures designed from the outset for efficient partial-load operation, frequent cycling tolerance, intrinsic gas separation, and durability under the actual renewable-power profile.

• semanticscholar https://doi.org/10.2118/235731-msfirst seen 2026-11-05 05:56:05 · last seen 2026-11-06 05:29:01