Celtic Sea Power needed to understand how hydrogen pipelines and electrical cables could safely share space offshore and onshore. Apollo’s study assessed the risks, identified gaps in guidance, and proposed practical design solutions for co-location.
The problem
Hydrogen and high voltage don’t mix. At least, not without careful planning.
Celtic Sea Power identified a risk where high-voltage (HV) cables, laid close to steel hydrogen pipelines, could cause negative effects to the hydrogen pipeline.
The concern? AC corrosion and integrity issues that could impact safety and operations. With no established guidance to fall back on, this issue needed to be addressed early in the design stage.
The background
The Milford Haven: Hydrogen Kingdom (MH:HK) project is a collaboration between Celtic Sea Power, Dolphyn Hydrogen, Wales & West Utilities, and the Offshore Renewable Energy Catapult. Together, they aim to accelerate the production of affordable low carbon hydrogen at scale. MH:HK will progress the design and consent for a project producing green hydrogen offshore in the Pembrokeshire Demonstration Zone (PDZ) in a world first hydrogen from floating wind development. Accelerating the production of low carbon hydrogen for South Wales and the Celtic Sea region.
Taking the south Pembrokeshire peninsular as an example, there are a number of electrical cables installed or planned in those waters, making landfall at Freshwater west and other locations. The MH:HK project is examining the feasibility of landing a hydrogen pipeline on this peninsular, and will have to co-exist with this existing and planned infrastructure. The approaches to the shoreline have many protected and restricted areas and therefore infrastructure may have to share very restricted routes through reefs, wrecks etc. to make landfall. Additionally, MH:HK is examining the feasibility of a hydrogen reception facility within the south Pembrokeshire peninsular and will have to co-exist with existing and planned electrical infrastructure.
A detailed study was needed to assess the risk and explore potential solutions.
“Apollo were the obvious choice of partner to deliver this study, with their experience in both oil & gas and electrical infrastructure. The study outputs have been critical in addressing potential technical challenges to the MH:HK ambition to bring green hydrogen ashore on the south Pembrokeshire peninsular. By analysing how high-voltage cables and hydrogen pipelines interact, Apollo identified real risks and defined practical mitigations. Apollo were able to convey highly technical principles and outputs in a manner that can be disseminated to a wide range of stakeholders”.
– Nigel Jones, Technical Manager, Celtic Sea Power
The process
Working in support of the MH:HK project, Apollo conducted a study to understand the potential interference risks.
Our team reviewed existing standards, regulations, and available guidance. We examined the potential interaction between HV cables and steel pipelines, considering both mechanical and electrical aspects. A literature review, technical analysis, and input from specialists helped us identify gaps in current industry knowledge and design practices.
The solution
The study proposed a framework for safe, co-located cable and pipeline design.
It covered both offshore and onshore conditions, outlining different scenarios where interference might occur. Where risks were identified, mitigation measures such as burial techniques, physical separation, and protective barriers were suggested. The work also highlighted opportunities to refine guidance and provide more robust support for design decisions across future projects.
The outcome
The study gave Celtic Sea Power and its partners a clear understanding of interference risks and how to manage them.
It informed design discussions, supported stakeholder engagement, and strengthened the drive to build integrated hydrogen infrastructure within the £3.5 billion Milford Haven Future Energy Cluster – a valuable step toward a smarter, safer route to net zero.
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