Project Summary

This project is undertaking 'full-scale' testing with the aim of validating models forerosion, vibration, noise, and particle transportation in hydrogen flow conditionsthat would likely exist in a converted natural gas network for the purpose ofcontributing to the heat transformation necessary to meet the 2030 and 2050emissions targets. The project meets the Heat challenge aims to "produce insightsand findings which facilitate decision making for low carbon heating by the energynetworks, industry and government".

Project partners include all the gas distribution network operators (SGN, Cadent,NGN and WWU), National Gas Transmission, Institution of Gas Engineers andManagers (IGEM), and DNV. Collaboratively working with these project partners,we aim to understand how hydrogen network constraints can be minimised at thelowest economic cost.
The energy network innovation for hydrogen networks has evolved in recent yearsfrom desktop studies to multiple large-scale tests, and several live trials, forexample Hydeploy, and proposed future trials such as H100 and the HydrogenVillage trials.
The Discovery phase of the project established that there was insufficient datathat could be relied on to define suitable design standards for Hydrogen andHydrogen-Natural gas mixtures in UK gas pipes.
The Alpha phase of this project was predominantly desktop based and includedthe following activities:

• erosion modelling
• particle transport modelling
• vibration and noise modelling
• laboratory scale tests to investigate possible synergistic hydrogen embrittlementand erosion]
• a conceptual design of full-scale test facility
• a draft test plan for undertaking tests to assess/ validate the hydrogen velocitymodels
• cost/ benefit modelling to assess the remediation costs associated withhydrogen velocity limitations

The perception of the challenge involved with higher hydrogen velocities hasremained largely constant, however it has become apparent that there is anincreasing need to communicate with other ongoing projects to ensure efficienciesand compatibility of proposed solutions, and that it will be important to ensure thata standards body such as IGEM is involved throughout the project to ensureindustry buy-in.
The key users for this demonstration project are the gas distribution andtransmission network operators who need to understand how to apply safehydrogen design velocity limit to their networks, to ensure the integrity of thepressure system is maintained whilst supplying the required energy output, at thelowest economic cost
Project partners:
SGN, WWU, Cadent, NGN, National Grid Gas
The gas distribution and transmission networks are responsible for the design,operation, maintenance of the existing natural gas networks, with expertise and competence in managing below ground and above ground pipelines andinstallations.
Institution of Gas Engineers and Managers (IGEM)
A professional institute, and the authors of the majority of gas transmission anddistribution standards used to design, operate, and maintain the UK's gasnetworks. IGEM's technical committees are responsible for technical and editorialupdates of the standards, which are then adopted by the gas network operatorsfor use in business as usual.
DNV
DNV is a global leader in technical assurance and risk advisory for oil and gas.The DNV team in the UK has subject matter experts in materials and fitness forservice, and in the design, construction and operation of full-scale test facilitieswhich utilise the Spadeadam test site. DNV has experts that have providedtechnical assurance for the gas distribution and transmission network operatorsfor decades.
The aim is to use the outputs from the full-scale tests to validate models that canbe used to set new hydrogen velocity limits that are supported by both theoreticaland empirical data. Validation is required as the networks could be operated in aregime where velocities are much higher than those in any previous validationtesting and historical operating experience.
The new velocity limits will allow the gas distribution and transmission networks,and any of their design sub-contractors, to design future hydrogen networks tomaintain the systems integrity at the lowest economic cost.

Innovation Justification

Gas engineers are required to design pipe networks to ensure that, at peakenergy delivery, the velocity of the gas does not exceed limits. These limits are toprotect pipe components from the effects of erosion from entrained debris, ornoise and vibration.
As Hydrogen delivers approximately one-third of the energy per unit compared tonatural gas, the re-purposing of existing assets to deliver the same energydemand will require an increased flow of gas.
If the design velocity limit is too low, substantial unnecessary reinforcement costswill be incurred as existing infrastructure is transitioned to carry hydrogen. If thedesign velocity limits are too high, asset integrity risk will be increased.

The current design velocity limits (natural gas) are long standing safe industrypractice. However, there has been no suitably representative research done onthe velocities at which Hydrogen will start to entrain debris and to a level thatcauses excessive erosion or causes other hazards due to excessive noise orvibration.
The Discovery and Alpha phases of this project showed:

• Insufficient valid data on the behaviour of 100% hydrogen and hydrogen-naturalgas blends to reliably establish safe velocity limits for these gases in UK gasinfrastructure
• The requirements of a full-scale test campaign to be conducted along with acost-benefit model to establish safe design velocity limits in representativeconditions.

An industry and stakeholder engagement plan, in the Beta Phase scope, ensuresthat the project results are accepted as valid and credible by the industry and usedto develop design codes and standards.

The gas engineering professional body, IGEM, will:

• Lead industry workshops to allow experienced professionals to challenge thedesign of the test rig and the planned test campaigns
• Commission a standards committee to develop suitable design standards forthe industry.

The post-project results will be:

• IRL 7 - The integration of technologies has been verified and validated withsufficient detail to be actionable: The results of the project can be relied upon tobuild safe design standards.
• CRL 8 -- Market Introduction: The design standards are available for theindustry to incorporate into their business-as-usual practices. The final CRLlevel 9 - Full Launch, may take some period after completion as networkoperators implement the practices into their design of networks to be "hydrogensafe".

The test campaign will be run on a test rig constructed at DNV's Spadeadam testfacility in Cumbria, making maximum use of the facilities and equipment alreadyavailable.
A full-scale test rig is:

• Needed to test actual pipe components and materials used in UK gasinfrastructure under the same operational conditions.
• Limited in the upper size of pipes tested to optimise the costs against datavalidity. Larger sizes of gas transmission pipe are less prone erosion and vibration due to their size and are designed to be cleaned. This also savessubstantial costs in the building of the test rig.
• Required as re-creating operational conditions at lab-scale is technicallychallenging and costly.

As the results of this project will be of benefit to the whole industry and ultimatelyconsumers during the energy transition, SIF funding is the best way to deliver thiswork. Network operators cannot fund this innovation research in their business-as-usual activities as

• It is required to build the safety case for the impending hydrogen transition
• They must ensure valid designs before they can introduce hydrogen into theirnetworks.

The project goes beyond incremental innovation by delivering data to driveimproved design standards used by the whole industry. SIF also provides an openplatform for sharing knowledge and project outputs, allowing for benefits to beshared to the wider industry.
Some counterfactual solutions have been considered and the outcomes detailedbelow.
Suitably representative testing done elsewhere or in other industries:

• None found

Apply existing design velocity limits:

• There will be substantial reinforcement costs that consumers will have to pay forto transition to low carbon heating.

Cleaning the networks:

• This is feasible (and common practice) for large diameter gas transmission linesthat are designed to have cleaning equipment ("Pigs") passed down theirlength.
• However, the smaller diameter pipes in lower pressure distribution networks andservice connections cannot be practically and economically cleaned for severalreasons.
• Much of the debris present in these networks is legacy from town gasdistribution and the lower pressures increase the possibility of ingress of debris.Further, the pipe diameters and design of the fittings make it impossible to runpigs through the pipes.
• To flush the pipes in multiple branched lower pressure networks, sections mustbe physically isolated that can be flushed using a suitable medium (that mustthen be captured and safely disposed). Each section must then be re-integrated, without any flushing media being retained, and without affectingsecurity of supply to consumers. This cost is prohibitive.

Benefits

The project will deliver cost reductions in operating the networks and wider energysystem.
Alpha phase network modelling looked at the network reinforcement requirements,using current design velocity limits, needed to convert a single low pressuredistribution network (Dundee used as a sample site) to 100% hydrogen.
The Dundee LP network has 575 km of pipe and was chosen as it was consideredto be representative of a medium sized distribution network in the UK.
The modelling showed that if the Dundee network was to deliver the same energywith 100% hydrogen while maintaining the required pressures (to ensure the safeoperation of downstream appliances) throughout the network, the addition of 17.7km of pipe at an indicated cost of £5.7 million would be required.
If gas design velocities are limited in this model to the current design standards(40m/s and 20m/s), the additional reinforcement cost would be increased to £5.9million.
The total UK gas distribution network is made up of approximately 277,000 km ofpipe (of which about 93% is LP networks) and 23.6 million service connectionpipes (connecting Consumer's meters to the gas distribution pipe).
Work completed in the Hydrogen Ready Services project, part of the NIA fundedH21 suite of projects, showed that that approximately 15 million services wouldhave a future supply issue on 100% hydrogen, based on a 5mbar pressure dropcriteria, 20 million if the velocity restriction (currently 15m/s) cannot be increasedat times of peak demand.
Also built into the CBA is assumptions around the likely change in number ofconsumers receiving heat energy from hydrogen after the energy transition usinglatest future energy scenarios produced by the Energy Systems Operator.
The Cost Benefit Analysis submitted with this proposal (in the ProjectManagement Book) analyses the reinforcement costs that can be avoided if thedesign gas velocities can be safely increased, using conservative assumptionsaround the likely hydrogen energy consumption after the energy transition.
The CBA shows that the Whole Life NPV delivered to Consumers by the deliveryof this project will be £1.55 billion, defined in the Adopted Option 1 in the CBA.
A more conservative Rejected Option 2 in the CBA is based on the projectshowing that a marginal increase in design velocities is safe, resulting in a reduction in reinforcement costs avoided, and delivers a Whole Life NPV of £383million.
NPVs over shorter periods for Adopted Option 1 in the CBA:
1 year: £0.08 million
3 year: £0.35 million
5 year: £19.37 million
10 year: £107.2 million
Should the project results indicate a marginal increase in design velocities is safe,the shorter term NPVs from the Rejected Option 2 in the CBA would be:
1 year: £0.08 million
3 year: £0.35 million
5 year: £4.23 million
10 year: £25.73 million
The Beta phase Total Project Cost is £6,554,978.00 of which £5,912,134.00 of SIFfunding is proposed.
In the Beta Phase, additional analysis will expand to include the effects of designvelocity on medium and intermediate pressure networks, Pressure ReducingStations (PRS), other Above Ground Installations (AGI).
The analysis will use the test data delivered by the project to evaluate theoptimum cost-benefit to balance reduced reinforcement costs without increasingintegrity risk to UK networks during the energy transition.