An Operators Experience in Developing a Technical Strategy for Repurposing the UK National Transmission System (NTS) to Transport Hydrogen

Abstract National Gas Transmission (NGT) own and operate the 7660 km National Transmission System (NTS) in the United Kingdom (UK) and have a responsibility to develop the green energy system for the future, while delivering the natural gas needs of today. There is worldwide interest in repurposing existing pipeline transmission systems from transporting methane to hydrogen. Extensive research is being conducted to understand the implications that hydrogen may have on design, materials, integrity and the resulting safety considerations. The effective application of the developing research requires a robust technical strategy for repurposing that is underpinned by comprehensive technical procedures which address: the data requirements, the technical assessments to be performed and their reporting requirements. This paper will describe: - How NGT via Project Union will facilitate an efficient route to net zero and a hydrogen economy by repurposing existing high pressure natural gas pipelines in the NTS to create a hydrogen ‘backbone’. - The challenges resulting from hydrogen operation. - The design and construction basis of the UK NTS and how this understanding is being utilized to develop a hydrogen repurposing methodology. - The Code challenges in hydrogen repurposing. - A previous ‘change of use’ UK project and its relevance to hydrogen repurposing. - An outline methodology for hydrogen repurposing of UK pipelines and installations, which takes due cognisance of the hydrogen challenges, Code requirements and the good practice that has previously been experienced in UK ‘change of use’ projects. - The opportunity for digital transformation when developing and applying a repurposing methodology. - The ongoing stakeholder challenges for regulators, code bodies, pipeline operators and service providers.