The National Grid FutureGrid hydrogen test site - how the UK operator learns to repurpose gas pipelines

National Grid FutureGrid hydrogen test site sits in the drizzle at Spadeadam, steel pipes beading with moisture as technicians listen to the faint hiss of gas moving through a repurposed high-pressure line. This is not a lab bench experiment, but a full?scale mock?up of the UK’s future hydrogen backbone.

From gas grid to hydrogen testbed

FutureGrid is National Grid’s large-scale research project that connects full-length decommissioned gas transmission assets into a test loop to experiment with transporting hydrogen and hydrogen blends. At the Spadeadam Research and Development Centre in Cumbria, engineers can safely push increasing hydrogen concentrations through real pipes, valves and compressors that once carried natural gas across Britain.

Project director Lorna Millington describes FutureGrid as a “replica transmission system” where National Grid can learn how hydrogen behaves inside legacy steel assets over long periods, rather than relying only on short-duration lab tests. The site includes above-ground pipework, buried sections, valve pits and pig traps, configured to mimic typical UK transmission routes and operating pressures.

Technical backbone and test program

The test loop in FutureGrid uses around 13 km of retired high-pressure transmission pipe, assembled to operate up to around 40 bar with hydrogen blends in early phases and progressing to higher hydrogen contents as safety cases are proven. Sensors track pressure drops, leak behaviour and material responses along the loop, giving National Grid detailed data on how different steel grades and weld types respond to hydrogen embrittlement risk.

National Grid works in FutureGrid with partners such as DNV, the UK government’s Net Zero Innovation Portfolio and academic teams to design test campaigns and interpret results. Many trials focus on how up to 20% hydrogen blends might flow in existing gas lines, but later phases target 100% hydrogen transmission, including start-up, shutdown and emergency venting scenarios.

What National Grid wants to learn

The FutureGrid program is designed to answer very practical questions: Can existing line pipe safely carry hydrogen for decades? How might control systems and compressor stations need to change? What happens at offtakes, pressure reduction stations and customer connections if hydrogen is introduced?

For example, some trials examine whether hydrogen blends affect the integrity of flanges, seals and valve seats differently than methane, especially under frequent thermal cycling. Others test how odorants used to detect gas leaks behave with hydrogen and whether new odorization standards are needed for a converted grid.

Safety cases and regulation

FutureGrid also feeds into the UK Health and Safety Executive’s regulatory thinking on hydrogen transmission. By generating real-world evidence on leak rates, dispersion patterns and ignition probability around typical above-ground installations, National Grid can support robust safety cases for any future hydrogen backbone corridor.

FutureGrid includes controlled release tests, with small hydrogen leaks monitored by gas detectors and cameras, allowing emergency procedures to be refined. These tests happen in open air at the Spadeadam site, where controlled wind and weather conditions can be simulated to understand dispersion in different scenarios.

Hydrogen blends versus full conversion

National Grid uses FutureGrid to compare two core pathways: modest hydrogen blends in the existing gas network versus full conversion of certain routes to 100% hydrogen. Blends could lower emissions quickly while using existing boilers and industrial burners, but they offer limited decarbonization and may complicate metering and billing.

Full hydrogen conversion along designated corridors would enable deep decarbonization of heavy industry and power generation, but it implies complex sequencing: turbines, industrial furnaces and storage facilities along the route must all be ready to take hydrogen before pipelines switch. FutureGrid’s data help assess the feasibility and timing of such corridor plans.

Industrial and power applications

National Grid’s FutureGrid work ties directly into potential hydrogen demand clusters such as Teesside, the Humber and the North West, where refineries, steel plants and chemical sites could one day draw hydrogen from converted transmission lines. The test site’s findings inform early designs for projects like the East Coast Cluster and HyNet, even though those are separate consortia.

On the power side, FutureGrid is relevant to National Grid’s thinking on future gas-fired generation units that could be adapted to burn hydrogen or hydrogen blends. Understanding transmission behaviour is necessary before any large hydrogen-ready turbines can be connected to a backbone and expected to ramp fast to balance wind and solar output.

Materials science on the pipe rack

One of FutureGrid’s quieter but critical contributions happens in materials labs, where coupons taken from the test loop are examined for signs of hydrogen embrittlement or stress corrosion cracking after exposure. Metallurgists look for microcracks along welds and the heat-affected zone, measuring how different steel grades respond.

These tests can reveal whether certain generations of pipe are unsuitable for hydrogen without mitigation, such as lower operating pressures, internal linings or full replacement. That, in turn, shapes asset strategies, allowing National Grid to map which segments of the gas transmission system could be converted and which are likely stranded from a hydrogen perspective.

Operational controls and digital tools

FutureGrid is also a playground for trying out digital twins and advanced monitoring technologies on hydrogen lines. National Grid and its partners instrument the loop with fiber-optic temperature and strain sensing, acoustic leak detection and high-frequency pressure measurement, feeding data into models that mirror the physical network in real time.

Control room operators and analysts can then rehearse hydrogen network operations, including ramping flows, responding to disturbances and planning maintenance outages. This helps identify whether existing SCADA and pipeline control systems can be adapted for hydrogen or need more fundamental redesign to handle different compressibility and flow dynamics.

Cost, timelines and funding

FutureGrid has been supported by UK government innovation funding, including grants from the Department for Business, Energy & Industrial Strategy and Ofgem’s Strategic Innovation Fund. Public money reflects the project’s system-level importance: as a regulated transmission operator, National Grid needs evidence to justify any large-scale hydrogen investments delivered through future price controls.

Some phases of FutureGrid run over several years, with discrete test campaigns scheduled to inform regulatory milestones such as the UK’s decision on blending limits in the gas network. That means the project’s findings will feed into both policy decisions and National Grid’s own capital plans, long before customers feel any direct impact from hydrogen in their gas mix.

FutureGrid’s place among hydrogen test sites

Internationally, FutureGrid sits alongside projects such as Germany’s HyPerLink and the Netherlands’ HyStock efforts to understand hydrogen transmission and storage. However, the UK site stands out for its use of full-scale retired assets and its direct link to National Grid’s role as the owner of most of Britain’s high-pressure gas transmission system.

By testing on real pipes that once formed part of the National Transmission System, the project reduces the risk that lab-only results fail to capture quirks of field installations, such as aging coatings, soil conditions or complex junction geometries. That realism is one reason why FutureGrid is followed closely in European regulatory and utility circles.

Implications for customers and investors

For end users, FutureGrid’s work is mostly invisible for now. Gas still arrives like before, and hydrogen debates feel abstract. Yet the project helps determine whether the future decarbonization pathway leans more on electrification or also on repurposing the gas grid to carry low-carbon molecules where that is cheaper or technically easier.

For investors like those watching John Pettigrew’s National Grid PLC, FutureGrid is a signal of how the company is preparing for different net zero scenarios. The National Grid share on the London Stock Exchange reflects a regulated asset base model, and the hydrogen test site feeds into potential future regulated investments in repurposed or new transmission capacity.