Repurposing pipelines for hydrogen use
Revamping UK's gas pipelines for hydrogen
Transitioning UK's gas pipelines to accommodate hydrogen, blending into pure transport, aligned with growing hydrogen production.
The UK's transition to a hydrogen-based economy will require the development of a robust hydrogen transportation infrastructure to connect producers with consumers, support import and export activities, and enable system resilience and demand-side management. At present, natural gas pipeline networks fulfil these functions for the distribution and movement of natural gas. While new hydrogen pipelines could be built, economically speaking, the most favourable approach is to adapt existing natural gas pipelines for hydrogen use. It’s anticipated that this adaptation will start with the transportation of hydrogen-natural gas blends, evolving eventually to the exclusive transport of pure hydrogen, contingent on the escalation of hydrogen production.
Distribution networks
In December 2023, the UK Government decided to support adding hydrogen to gas networks in Great Britain (i.e. England, Wales, and Scotland), pending safety and economic assessments, driving early hydrogen economy development. This involves evaluating changes to regulations capping hydrogen in natural gas at ≤0.1%. Large-scale hydrogen blending could begin by 2025–26, with a future shift to 100% hydrogen contingent on policy reviews influenced by trial results in Fife and Europe.
The GB gas distribution networks are conducting research and trials to explore the feasibility of incorporating hydrogen into the existing gas pipelines. These efforts are focused on obtaining proof that up to a 20% hydrogen mix can be safely transported using the current infrastructure. A key research project, HyDeploy, has already completed two experimental deployments with a 20% blend of hydrogen: one in Keele University's private network in the English Midlands and another in a public network in Winlaton in the North East of England. HyDeploy has recently completed a third phase where it evaluated the implications for integrity and performance when introducing a 20% hydrogen blend across various pressure levels within the distribution networks, including pressures up to 70 barg as found in the local transmission system (LTS). The findings will contribute to governmental assessments regarding potential modifications to the Gas Safety (Management) Regulations (GS(M)R).
High pressure networks — the National Transmission System
Advancements in transportation capacity for hydrogen, both blended and pure, within the high-pressure National Transmission System (NTS), will primarily be determined by the projected trajectory of hydrogen generation and utilization across industrial sectors. This progress will occur irrespective of decisions made regarding hydrogen's role in domestic heating.
National Gas's FutureGrid programme analysed how to integrate hydrogen into the NTS by setting up a full-scale experimental facility using old pipes and equipment to test hydrogen mixtures and eventually pure hydrogen. The HyNTS programme conducts intensive lab tests on material behaviour and examines how hydrogen affects pipeline maintenance activities like corrosion control and repairs. Meanwhile, Project Union aims to transform current gas transmission systems into a hydrogen-only network by the early 2030s, having started preliminary engineering studies for this conversion in 2023.
Technical challenges of repurposing
Research must overcome various technical issues to repurpose pipelines on a large scale. The difficulty in obtaining detailed information due to the age and post-privatisation organisational changes of Great Britain's (GB) networks is one obstacle for assessing pipeline repurposing suitability. While data mining helps mitigate this, another major concern is the accelerated metal fatigue from cyclic pressure changes that hydrogen causes, unlike natural gas. This issue may affect the use of pipeline buffering as gas storage, a significant point since the UK has limited gas storage facilities. Additionally, ensuring compatibility of existing compressors with hydrogen and its mixtures presents challenges; even as manufacturers work to adapt, it is probable that some compressors might need replacements or updates for effective hydrogen network operation.
Interested in the future of hydrogen?
The latest edition of DNV’s UK Energy Transition Outlook showcases the fundamental shift in energy generation that will revolutionize the sector, as the focus moves away from fossil fuels and towards variable renewable energy sources.
We don’t sugar coat the challenges that await around the uncertain role of hydrogen and the lack of government policy. Nor do we underplay the enormous opportunities that transitioning our energy system will create.
9/11/2024 8:00:00 AM