NATIONAL GAS: Repurposing the UK’s Energy Backbone

Across the UK energy system, few assets are as central – or as underappreciated – as the thousands of miles of pipelines quietly transporting gas between terminals, storage facilities, industrial clusters and power stations. Built over decades, the network underpins energy security and economic productivity. Yet the same infrastructure now sits at the centre of one of the most important engineering transformations of the net zero era.

For National Gas, the operator of Britain’s national transmission system, the challenge is not simply about replacing natural gas with a new fuel. Instead, the task is far more complex and far more exciting: adapting a vast existing network so it can carry the molecules that will define the future energy system.

Hydrogen, captured carbon dioxide, biomethane and natural gas will coexist in a new ecosystem. Repurposing assets wherever possible will reduce costs, accelerate deployment, and avoid stranding infrastructure that still has decades of technical life remaining. The result is a strategy that combines innovation, pragmatism and large-scale engineering.

“We are the innovation team at National Gas and over the last five years we’ve been building up the evidence for new molecules – hydrogen and carbon transportation – mostly looking at repurposing our network, but also considering what it would mean to build new pipelines as well, which we haven’t done for a reasonable amount of time,” explains Corinna Burger, Director – New Molecules.

The thinking behind that work is rooted in a simple reality. The UK’s transmission network stretches roughly 5,000 miles across the country, connecting key import terminals, storage facilities and industrial hubs. As industries begin to decarbonise and new fuels emerge, the infrastructure must adapt rather than be abandoned.

“Repurposing is key because obviously we’ve got a lot of infrastructure in the UK that if we move away from natural gas could be stranded, and moving with the times and looking at hydrogen and carbon is a positive for not just the consumers in the UK but also government and other interested parties – that is really our focus,” she adds.

This approach has been backed by a growing body of research, testing and engineering analysis. The company has spent years developing a detailed technical understanding of how different parts of the network behave under new conditions – from pipeline metallurgy to the digital monitoring systems required to manage new flows.

Part of the process has been conducted in partnership with Element Materials Testing, a leading lab and field testing, inspection and certification organisation with a vast skillset. This work has included a study of fracture mechanics in pipelines during a transition to hydrogen as well as the management of safety data across sites in relation to hydrogen.

“We’ve looked at a bottom-up approach for repurposing. That means looking at the technical case for each of the asset types – what materials they’re made of and what digital systems need to sit around that. Element has been key in this process providing testing certainty which is extremely valuable,” says Burger.

The scale of the evidence gathered is vast. Dozens of test programmes, engineering trials and modelling exercises have gradually built the case that the existing network can support the next generation of gases. That work is now approaching a key milestone.

“We’re now at a stage where we’ve almost finished much of the research, so as of April 2026 all the 100% hydrogen evidence will be ready to go. We’ve already submitted the blending evidence and the CCS will follow.

“The evidence provides the Health and Safety Executive (HSE) with a pack of information to then approve us moving forward with hydrogen and carbon, and that’s what they’re reviewing at the moment as part of a wider consultation,” Burger confirms.

Once approved, the work will move from experimentation into the operational frameworks that govern the national network. Translating years of technical work into practical standards is a significant undertaking.

“When the HSE is happy, we’ll be starting to pull that into our policies and standards and the innovation team is doing a fabulous job of trying to collate over 200 projects, with hundreds of pages of technical documents for each into clear, concise standards that the business can use.”

Behind the scenes, new digital tools are helping to bring this huge body of research together.

“We have been looking at some novel AI tools to support with that, and then we’re looking at how we pull that into operations, making sure that we can operate our network and making sure we have methodologies and standards in place.”

Crucially, the shift from theory to reality is already underway. Burger herself is moving from innovation leadership into construction, ensuring that the knowledge gained through years of testing becomes embedded in the projects now being designed and built.

“That means we will be leading on the ProjectUnion FEED studies, as well as others, and that is very exciting for all of us,” she says.

ProjectUnion is a National Gas flagship development that has already received multimillion pound investment from OFGEM with a goal of connecting industrial clusters around the north of England and into Scotland, creating a hydrogen network that will unlock major future potential for economic growth and industrial performance.

INNOVATION IN ACTION

Much of that evidence has been generated at one of the most unusual energy facilities in Europe. Located in Cumbria, FutureGrid has been developed as a full-scale hydrogen test an demonstration network, allowing engineers to replicate real-world transmission conditions and explore how existing infrastructure behaves when transporting new gases.

“We’ve got some big programmes ongoing at the FutureGrid site in Cumbria,” Burger explains.

“It’s a world-first facility, it has taken a number of repurposed assets from across our network and built them into a mini network with an entry point, an exit point, and all the assets you’d find in between.”

The facility includes valves, compressors and pipeline sections taken from the live transmission system and reassembled into a working network. This allows the team to run controlled experiments that would be impossible on operational infrastructure.

“Phase One testing finished there last year and we demonstrated that we could run blends and 100% hydrogen through those assets successfully with no operational issues.”

Those results represent a major step forward for the UK hydrogen economy. Hydrogen blending is widely viewed as a potential bridge technology, enabling the gradual introduction of hydrogen into the existing gas system while dedicated hydrogen networks are developed.

National Gas has been a strong supporter of this approach, highlighting its potential to unlock early demand and accelerate investment in production.

At FutureGrid, the research is now moving beyond basic compatibility testing into real-world applications.

“We’ve now developed that further to start to look at transportation, discovering if we can link fuel stations from across the UK into our network and provide 99.9% pure hydrogen to a fuel cell.”

The ability to transport hydrogen through existing pipelines and deliver high purity gas to end users could open the door to entirely new markets, particularly in heavy transport and industry.

“Transport in a network, especially a repurposed network, means that you have to purify the gas that comes out,” Burger says.

“But we are working with some really nice technologies that will allow us to do that without needing moving parts or large compressors – that is really impressive.”

FutureGrid is also supporting the development of carbon capture infrastructure, another cornerstone of the UK’s net zero strategy. Industrial clusters in Scotland and northern England are expected to rely heavily on carbon transport networks linking factories to offshore storage sites.

“Using that same facility in Cumbria, we’re also going to demonstrate that we can transport carbon and that’s for our CCUS projects, focused on Scotland at the moment, taking emissions from Grangemouth and transporting them up to the Acorn Project site at St Fergus Gas Terminal,” explains Burger.

Beyond the technical findings, the site has become an important demonstration tool for policymakers and industry partners.

“This whole project allows us to say ‘look, we can do this’. We can now bring people along, talk them through the process and what it means and for our network, that that is hugely beneficial beyond just National Gas.”

STRESS TESTING

Behind the scenes, extensive testing is also examining the long-term durability of infrastructure operating under new conditions.

“We have a number of offline test facilities. We’ve been looking at what happens if there’s a rupture, for example. What’s the consequence of failure and how do we avoid that? We are also looking at fatigue – if we run the network for 200 years with hydrogen, what is the impact?

“Our fatigue rig has actually been running now for a long time, with years’ worth of fatigue cycles, which is a fantastic achievement and there has not been any failure of that that asset.”

The practical outcome of this research is beginning to take shape through major infrastructure programmes such as ProjectUnion, a proposed hydrogen backbone designed to connect Britain’s major industrial clusters.

The concept would link regions such as the Humber, Teesside and Merseyside through repurposed pipelines, before looking south, enabling hydrogen production sites to supply multiple sectors across the country. National Gas has already secured funding to begin early development of these routes.

“When it comes to what’s next, our three-molecule approach is very important. We’re doing work on hydrogen, carbon and natural gas, and we have an ambition in the UK to blend into the 5000 miles of pipeline that already exist across all of the network that we have,” Burger explains.

At the same time, the network must remain flexible enough to accommodate new sources of renewable gas entering the system.

“We’re also looking at increasing the biomethane connections into our network projects and looking at how we speed up connection processes,” she adds.

“We are looking at how we create standardised designs for those connections so that it’s easier for our customers to connect and that is all part of our very exciting ProjectUnion.”

For Petherbridge, the complexity of the future system will demand a network capable of moving energy in entirely new patterns.

“As we go towards 2030 and beyond, it becomes even more complicated, especially with clean power. We’re going to need to be able to move gas more all over the country as required.”

At the same time, maintaining the reliability of the existing system remains essential. Many compressor stations, terminals and other assets were built decades ago and must continue to operate safely throughout the transition.

“In terms of the focus on what we’re doing with our natural gas research, it’s all about reliability and resilience,” she says.

“A lot of the operation and maintenance technologies are getting better and we are looking at how we start to utilise some of those new technologies to make ourselves more efficient and cost effective as a network moving forward.”

PARTNERSHIP PROMISE

Delivering this transformation is not something National Gas can do alone. The programmes underway involve a broad ecosystem of partners, from engineering firms and academic researchers to regulators and other transmission system operators.

“These test projects are collaborative – we’re actively working with DNV (specialists in pipelines and safety) on their sites,” Burger says. “We work closely with the HSE where we’re a partner to make sure that we were doing the right things and sharing the right information.”

Industry partners across the UK are also contributing to the work and international collaboration has played an important role as well.

“We have been working closely with Northern Gas Networks on future projects, and we’ve involved industry specialists such as Cadent and SGN and more.”

“At the same time, we work closely with Fluxys, the Belgian TSO which brought £2million of research into our projects as they don’t have a test facility like we do, but they have extensive and valuable lab research.

“We’re also partnering extensively with ROSEN on hydrogen knowledge and critical lab-based materials research,” adds Burger, who says the scale of cooperation reflects the shared challenge facing the entire energy sector.

“This level of collaboration is unheard of across other industry sectors and creates a very strong position for National Gas as we look to the future.”

The objective behind that collaboration is straightforward.

“Ultimately, the goal is to get the right partners together, with the best technical expertise, so that we can create appropriate solutions for minimising costs for UK consumers.”

As the UK’s energy system continues to evolve, the pipelines that once carried only natural gas are poised to become the arteries of a much more diverse energy network. Hydrogen, carbon dioxide and renewable gases will soon share space within the same infrastructure, supporting industries, power systems and emerging transport sectors.

For National Gas, the transformation represents a rare opportunity: to modernise one of the country’s most critical assets while building the backbone of the next energy economy.