National Gas Transmission (NGT) own and operate the UK’s National Transmission System (NTS), transporting natural gas from terminals to end users. NGT have ambitions to repurpose the existing to transport hydrogen and hydrogen blends. Understanding the impact of hydrogen on our existing assets is a key enabler for this.
This project will determine the impact of hydrogen and blends on our gas pre-heating systems. Gas pre-heating is used in a range of operations, primarily to avoid liquid-drop out due to the Joule-Thomson effect when reducing the pressure of natural gas. The project will involve assessing the current assets and procedures for gas pre-heating with hydrogen and blends, determine any upgrades or modifications required, and review current procedures to assess their applicability to gas-preheating with hydrogen.
Benefits
The benefits of this project are in determining the key differences between pre-heating system for natural gas and hydrogen and consider if additional changes are required to the current NTS assets. This is vital information to understand the capabilities of existing assets with hydrogen and any modifications or new equipment required. Hydrogen will provide long term decarbonisation opportunities for the UK and is key to our net zero targets
Learnings
Outcomes
Value tracking Data Point Data Point Definition
Maturity TRL 2-4 The maturity of the existing uprating process is advanced, consideration
for how hydrogen impacts this new process has not been made and
therefore the TRL is low at the start of this project but should rapidly
increase.
Opportunity 100% of single asset class The project will cover only pre-heating system.
Deployment costs - The project is not delivering something that will be deployed on the
network.
Innovation cost £242,233.33 The cost of the innovation includes a desktop study,
site visits (travel), reporting and project management.
Financial Saving - The project may result in financial savings if the findings can be used to
avoid costly changes to Pre-heating system and configurations however
this will not be realised within this work.
Safety - The project can be taken forward to update policies and procedures for
hydrogen, which will enable safe operation and maintenance of the NTS.
Environment - The project will not have any direct CO2 savings but will help
enable hydrogen in the NTS.
Compliance Ensures compliance The project will support compliance with relevant safety standards for
safe operation of hydrogen network in the future.
Skills & Competencies Individuals Individuals directly involved with the project will gain an understanding
into the hydrogen networks and current NTS assets designs with
hydrogen.
New tool, skills and competencies will need to be developed across the
departments.
Future proof Supports business strategy The project will help enable hydrogen in the NTS and support the energy
transition.
The project has the potential to influence future decision-making, such as RIIO-3 investment to enable NTS network decisions on future hydrogen transmission infrastructure.
Lessons Learnt
Project delivery learnings
· There were a minor delay in receiving data from FutureGrid testing. Wood has managed to spare the resource and complete the study within the delivery time for Phase 1.
Technical learnings
· Selection of Equation of State (EoS) is critical for accurate Joule Thompson effect prediction of change in temperature due to expansion of gas. Prediction of JTC via laboratory experiments is complex, physical operation with blended hydrogen gas can be used to tune the simulation models.
· Simulation results showed excellent match with FutureGrid Data, thermodynamic models can predict J-T cooling for hydrogen and natural gas blended systems with reasonable accuracy. GERG2008 EoS showed better predictions for 100% hydrogen gas compared to Peng-Robinson.
· For design purposes, it is recommended to tune the models as per FutureGrid data and take appropriate margins to ensure pre-heating systems are adequate to handle blends of hydrogen.
