Offshore Hydrogen Production in the North Sea Enables Far Offshore Wind Development

Abstract

The North Sea area is in transition. While oil and gas production is in decline, the deployment of offshore wind turbines in large scale wind parks to produce offshore renewable energy is accelerating. The accelerated deployment of renewable wind increasingly far offshore creates challenges to transport large amounts of energy to shore. Traditional energy transport from offshore wind by means of HVAC power cables becomes uneconomic beyond 100 km from shore and energy losses are unacceptably high. Moving to HVDC cables reduces the power losses, but increases the cost of power conversion offshore. An alternative that currently is being considered is energy transport via molecules, in the form of hydrogen. The hydrogen is produced from seawater after desalinization by means of water electrolysis. The current pipeline infrastructure in the North Sea can be reused to transport the hydrogen at high pressure and low cost to shore. As large industry sectors are considering decarbonization by means of hydrogen, in particular for hydrotreatment, desulfurization and ammonia production, the so called ‘green’ hydrogen can directly be used onshore without reconversion to power. Half of the assets in the North Sea are approaching end of life and decommissioning in the coming decade, which means they become available for re-purposing. Most offshore trunk lines also operate under their maximum capacity. Prior and ongoing research projects are aimed at identifying win-win combinations from this situation: to re-use platforms for hydrogen production (P2G), pipelines for hydrogen transport and perhaps wells for hydrogen or CO2 storage such that the variable nature of wind power can be exploited more efficiently. The objective of the PosHYdon project, the first offshore hydrogen production plant is not only to build up experience with the production of H2 in an offshore environment, but it will also be a test center for innovative Power to Gas (P2G) technologies and integrated systems. The aim of the facility is to accommodate at least 1 MW of electrolyzer capacity, including its water treatment unit and auxiliary units. The objective of the project is to gain experience with the operation of a hydrogen production unit offshore, and the admixing of hydrogen in an multiphase flow pipeline carrying oil and gas towards a process separation and treatment hub located nearby. The pilot seeks to gain more detailed information on cost of installation and operation of an electrolyser unit in an offshore environment.