Study Compares Fixed Wind Architectures for Offshore Green Hydrogen Production

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This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper OTC 32317, “Fixed Wind Architecture Comparison for Offshore Green Hydrogen Production,” by Dominic Pliszka, Catherine Gourlay, and Nihad Abdullazada, Subsea7, et al. The paper has not been peer reviewed. Copyright 2023 Offshore Technology Conference. Reproduced by permission.

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The complete paper is a summary of a study that covers through-life economics for producing green hydrogen from offshore fixed wind turbines. The options compare production of hydrogen on the turbine itself (decentralized) with production on a dedicated production platform (centralized) and production from an onshore facility. The results of the economic analysis show that decentralized hydrogen production can be competitive against onshore production at longer offshore distances.

Introduction

The paper contains a summary of an offshore green-hydrogen-production study performed by a group of companies. The field architectures for each of the evaluated cases are described and the results of the economic analysis are presented in the complete text.

Field Architecture Layouts

The hydrogen production cases in the study are divided into three architectural layouts.

Case 1: Onshore Hydrogen Production. The electricity produced at the offshore wind farm is gathered by interarray cables and directed to an offshore substation. From this location, the combined power is transported to an onshore hydrogen production facility through offshore export cables. Case 1 (the base case) is used to benchmark and compare the results against Cases 2 and 3.

Case 2: Offshore Hydrogen Production (Decentralized). The electricity generated by each offshore wind turbine is directed to a hydrogen production unit specific to each of the turbines, and green hydrogen is produced. Hydrogen is collected and exported through a dedicated hydrogen transport line to onshore facilities. Case 2 also is referred to as a wind farm with a decentralized hydrogen production system. In this scenario, a gas compressor located on each wind turbine is considered.

Case 3: Offshore Hydrogen Production (Centralized). The electricity produced at the offshore wind farm is directed to a hydrogen-production facility at a centralized offshore substation. The hydrogen from the substation is exported through a dedicated hydrogen transportation line to onshore facilities. This scenario is also referred to as a wind farm with centralized hydrogen production system.

Wind-Farm Overview

A single wind turbine with a maximum power output of 15 MW is assumed as the basis of this study. The wind farm has 67 turbines on fixed monopile foundations, giving a power rating of 1 GW. The wind turbines will be connected in a daisy-chain manner, each chain containing eight or nine turbines.