RWE plans to begin commercial production at Europe’s largest green hydrogen plant this year. The first 100 MW electrolyzer at the GET H2 Nukleus facility in Lingen, Germany is currently undergoing commissioning. There are plans to expand to 300 MW by 2027. This sets an aggressive timeline for engineering, procurement, construction and, critically, commissioning teams who will be responsible for turning a first-of-a-kind facility at this scale into a reliable, safe and certifiable operation.
Large green hydrogen plants share common building blocks: utility-scale electrolyzer arrays, high-capacity power conversion, demineralized water treatment, cooling systems, hydrogen compression and storage, oxygen handling, and a digital control layer that can respond to the intermittent nature of renewable electricity. Commissioning will need to validate each of those systems individually and then prove integrated performance against contract guarantees.
Key focus areas for commissioning and startup for green hydrogen include:
Power readiness.
Electrolyzers require large, stable DC power via transformers and rectifiers. Pre-energization checks, insulation resistance testing, protection relays, and grid-code compliance testing need to be sequenced with the interconnection operator.
Water treatment and balance of plant.
Green hydrogen quality depends on ultra-pure feedwater. Commissioning must confirm demineralized water meets conductivity and silica specifications, and that pretreatment, mixed-bed polishers, and reclaim streams function as designed. Cooling water or glycol systems must be flushed, chemically cleaned, leak-tested and balanced.
Electrolyzer arrays.
Whether PEM or alkaline, stacks typically arrive in modular skids. Factory acceptance tests shorten on-site work, but site acceptance tests still need to verify installation, interconnections, leak tightness, electrical integrity, instrumentation, and interlocks. Dry runs, nitrogen purges, and controlled first hydrogen generation are standard steps.
Safety and hazardous-area systems.
Hydrogen detection, ventilation rates, classified-area compliance (ATEX/IECEx), emergency shutdown logic, and fire protection must be validated before introducing hydrogen or oxygen. Functional safety teams should complete HAZOP closeout actions, LOPA reviews, and safety integrity level proof tests ahead of live operation.
Compression, storage and dispatch.
Post-electrolyzer hydrogen is typically delivered at low to medium pressure; compressors lift to pipeline, trailer, or onsite storage pressures. Commissioning should include pressure testing, performance mapping, knock-out pots and dryer checks, thermal management, and blowdown/inerting procedures. Storage vessels need hydrostatic or pneumatic testing and instrumentation calibration.
Oxygen handling.
Oxygen is a coproduct. Vent stacks, silencers, materials compatibility, and any sale or reuse systems require verification to prevent enrichment hazards.
Controls, metering and certification.
Distributed control systems and safety PLCs must undergo loop checks and cause-and-effect testing. Revenue-grade metering and energy accounting are important not only for offtake contracts, but also for green certification. In plants that pursue Guarantees of Origin or similar schemes, commissioning should validate the metering boundary, data integrity, and audit trails that link renewable electricity to hydrogen output.
Performance testing.
Owners and EPCs will need a test protocol that proves capacity, efficiency (kWh/kg), ramp rates, minimum turndown, purity to the end-use specification, and availability targets across multiple load points. Variability testing with renewable-like profiles helps de-risk commercial operations.
Interface with offtakers and networks.
Hydrogen will be transported via a 600-km pipeline to TotalEnergies’ Leuna refinery in Germany, so pressure, quality monitoring and custody transfer points must be commissioned with Germany’s GET H2 hydrogen network.
RWE placed its initial equipment orders in 2022, long before receiving confirmation of state support. The first two 100 MW electrolyzers were ordered from a consortium led by Linde and ITM Power. A third electrolyzer based on alkaline technology was ordered from German manufacturer Sunfire. By locking in supply chains early, RWE reduced bottlenecks that have slowed other European hydrogen projects. Early and complete factory acceptance tests, clear inspection and test plans, and a modular turnover strategy (systems and subsystems) can help keep the 2026 date intact. A punch-list strategy that prioritizes systems required for first hydrogen, followed by expansion to nameplate, is a proven approach at this scale.
Operations teams should be embedded early. Commissioning is the best phase to finalize operating envelopes, tune advanced process control for intermittent power, train shift crews on hydrogen and oxygen hazards, and stock critical spares such as stack components, compressor seals and valves, analyzers, and high-availability instrumentation. A digital twin or high-fidelity simulator can speed operator training and de-risk abnormal situation response.
Environmental and community considerations also intersect with commissioning. Water sourcing and blowdown quality must meet local permits. Noise from compressors and vent stacks should be measured against permit limits during performance tests. Emergency response plans with local authorities need drills before full-rate operation.
If RWE meets its timeline, the facility would set a new benchmark for scale in Europe’s green hydrogen sector. For the commissioning community, the project represents a chance to standardize practices for utility-scale electrolyzer plants—translating lessons learned on purity, safety, flexibility and certification into repeatable playbooks for the next wave of projects slated for the late 2020s.
Source: RWE to begin commercial production at Europe’s largest green hydrogen plant in 2026
Photo Credit: RWE
