Large-scale offshore hydrogen production is critical for decarbonizing hard-to-abate sectors, yet current models struggle with cost-efficiency. While centralized designs face infrastructure bottlenecks and decentralized concepts forfeit scale economies, semi-centralized architecture combines scale efficiency with operational flexibility.

EnBW, HydePoint, and Subsea7 present a techno-economic assessment based on the Dutch DEMO II Project. A 645 MW offshore wind farm supplies 480 MW of PEM electrolysis capacity, distributed across modular 120 MW and 160 MW platforms. Each platform is built around a standardized 20 MW building block, optimized for existing heavy-lift vessel envelopes to support serial fabrication and rapid scalability to gigawatt levels.

A business case model, utilizing hourly wind yields and day-ahead electricity prices, validates key design decisions and economics — including optimal hub configuration (3 vs. 4 hubs), infield cable routing and grid interconnector sizing. The model quantifies sector-coupling value and confirms the economic rationale for the semi-centralized approach under realistic market conditions.

The presentation covers wind-electrolysis interface management, onshore pre-commissioning strategies, risk mitigation and integrated installation campaigns.

This evidence-based study provides the hydrogen industry with a practical, scalable blueprint for commercial offshore production using today’s supply chain, i.e. existing offshore wind installation vessels and foundations.