Repurposing Typical GOM Platforms for Wind Power and Hydrogen Generation - Design and Economics

Abstract The ROICE (Repurposing Offshore Infrastructure for Clean Energy) Program at the University of Houston (UH) carries out studies on the design and economics of repurposing offshore platforms for wind power and wind to hydrogen projects. Here, findings on wind power and hydrogen project design for repurposing typical GOM platforms are presented, including decommissioning and topsides change out strategies, guidelines for placement of modules, and resulting project costs and paths to profitability. The ROICE program is taking a phased approach on the feasibility of repurposing offshore platforms in the GOM for clean energy such as wind power and hydrogen generation. Phase 1 of this study (OTC-35604-MS) developed the ROICE Levelized Cost (LC) Model, and generated LC maps for the GOM. Phase 2 work is presented here - integration of process modules such as transformers and electrolyzers and their placement on typical GOM platforms. A detailed economic model has been developed to study the impact of offtake prices, incentives and capex reductions and the potential for such projects to encourage timely decommissioning. A ROICE Cost Estimator model and Economic Model has been built for repurposing offshore structures for wind and hydrogen. Hydrogen and power module placement exercise was done for several typical offshore GOM deck layouts. Project economics were estimated for a range of project sizes, offtake prices, capex reduction, loan rates. Some key results: Cashflow from ROICE projects can cover the cost of both pre- and post-ROICE decommissioning. The challenge, however, is in generating an acceptable rate of return on investment for the ROICE project. Wind power, and H2 projects over a range of sizes are challenged at today’s capex.Hydrogen projects require a large footprint to accommodate electrolyzers, coolers, rectifiers and desalination units. Project size is thus limited by the available space on offshore platforms. More space-efficient designs for offshore installations are needed.ROICE projects can be profitable through a combination of low-cost loans and one or more of the following factors: Scale: Larger projects are more profitable. However, space availability on typical GOM platforms currently limits hydrogen project size to ~ 100 MW; wind power projects are less limited – can be as large as 500 MWGreen Premiums / Offtake Incentives: 2 to 5 cents of additional production tax credits (PTC) incentives needed for wind power; 2 to 5 $/kg additional 45V incentives needed for hydrogenCapex Reductions / Additional Investment Incentives: 30 to 50% reduction needed from 2023 capex; through design and technology improvements, supply chain resolution, tax incentives etc. This paper provides detailed information on typical project sizes that can be placed on offshore platforms, along with associated design, costs, and economics. It also identifies the path to profitability, and challenges therein, of such offshore clean energy repurposing projects.