Learnings

Outcomes

Summary
This work has explored various aspects of the existing South Wales Local Transmission System (LTS) and how it could play a role in hydrogen transportation within the South Wales Industrial Cluster (SWIC). The main aspect of the work has involved a detailed assessment of potential hydrogen demand out to 2050 across Low, Medium, and High hydrogen scenarios – where the Low hydrogen scenario represents gas use as it is today, and the Medium and High hydrogen scenarios reflect larger demands associated with hydrogen and industry.

These demand scenarios were then applied to the existing gas network topography to identify points of constraint, where the capacity of Above Ground Installations (AGIs) may prohibit the rollout of a hydrogen blend, and pure hydrogen, without further investment.

What this has generated is a tool to compare potential locations of centralised and distributed hydrogen production with network nodes where injection or sectorisation may or may not be appropriate. Further detailed analysis was undertaken in the Pembrokeshire region to fall in line with a sub-cluster of activity within SWIC and the basis for GW-scale hydrogen production in Milford Haven. The findings of this work have shown that this scale of production could satisfy a significant proportion of heat demand in South Wales and will likely form the basis for a targeted feasibility study as part of the latter stages of the SWIC Phase 2 Deployment project.

The work has also highlighted constraints around inter-day and inter-seasonal storage, where a need for further work has been identified to establish the basis for TW-scale hydrogen storage in the WWU region.

Development of Case Study Scenarios 

Regional demand scenarios have been defined based on future demand forecasts and the proportion of energy demand being met by hydrogen over time. Three scenarios have been developed: Low Hydrogen, Medium Hydrogen and High Hydrogen representing the likely hydrogen flows being transported in the network and the potential evolution through to 2050. 

Gas Network Modelling of Potential Network Configuration
It was identified and agreed that at this early feasibility stage, rigorous network modelling of hydrogen would be simplified to the evaluation of capacity of supply points against expected increase in volumetric gas flows for hydrogen scenarios. Current (1 in 20) peak gas flows (converted to the equivalent hydrogen flows for the study scenarios) is taken as the basis to assess utilisation of supply points capacity. 

It is appreciated that actual implementation will see some parts of the network having different proportion of demand from different users (e.g. domestic, industry, power generation, transport) and flows of hydrogen may be higher or lower than the assumed network average.  This is deemed to be representative and appropriate at this stage to generate the initial insights on network future scenarios. This evaluation is not intended to show a full conversion of the network but to assess the capacity of the network (supply point elements of the above 7 bar network, e.g. PRI valves, meters, piping) to transport the likely (100%) hydrogen flows and to provide initial insights into the network reinforcement required to provide additional capacity. 

Although the hydrogen flows have been evaluated (volumetric flows at standard conditions), the capacity evaluation is not a hydraulic model. No detailed evaluation of pipeline pressure losses and gas velocities above or below 7 bar (likely expected to increase above acceptable gas velocity for erosion) has been performed at this stage. Further work in subsequent phases should include a more detailed evaluation to include velocities and pressure drops in pipelines to approach rigorous hydraulic network modelling.

Evaluation of Network Configuration and Operation
The study has provided a high-level view on the capacity of the existing gas network to transport increased volumes of hydrogen, with a “high hydrogen” scenario representing an extreme case where hydrogen accounts for a large proportion of energy demand. To deliver the same energy demand than is currently supplied by gas, volumetric flows of hydrogen would have to increase by an approximate factor of 3 given the lower calorific value per unit of volume. Currently the network already sees high utilisation of the capacity of the supply points (PRIs). The network sections with more potential are those which have a lower utilisation currently, but network reinforcement is likely in the hydrogen supply scenarios by 2040-2050. 

The TRL of the project moved from 2 - 3

Lessons Learnt

An ambitious scope of work for the study was initially developed to support the investigation into the role of the gas network as part of the South Wales Industrial Cluster deployment project. The initial scope of work document was used to support the funding application for the SWIC Deployment Programme Phase 2 from the Industrial Strategy Challenge Fund (ISCF). As the SWIC scope is evolving, the initial scope of work for this study was indicative of the expected work that would provide value as the first study of its kind by WWU as a SWIC stakeholder.

A close collaboration was established between the WWU net zero and network operation team and the Costain decarbonisation consultancy team via frequent (weekly) progress meetings to 

1. Refine the scope of work based on
   • The status of the SWIC project at the beginning of the study, the knowledge of SWIC projects and the interdependency for integration into the cluster plan
   • The availability of data, methods and tools
   • The assessment of the work that would provide more value at the early feasibility stage, aligned to the overall objectives of the study
2. Review study progress, provide feedback/input and agree basis and methods
   • Incorporate views, opinions and encourage knowledge sharing from study stakeholders including technical consultants, network operations team, net zero project management and other SWIC stakeholders
   • Agree on assumptions and methods, with stakeholders fully aware of outcomes at the first opportunity

This collaborative approach allowed to tailor the study scope, based on trustworthy discussions which provided significant benefits to gain maximum value. This study was a first of a kind piece of work, examining the potential role for gas network in the SWIC deployment plan whilst considering practical considerations including network configuration and operation (particularly in regard to security of supply) and quantification of likely hydrogen demand aligned with SWIC ambitions for hydrogen production and roll-out.